Botox gone wrong: understand, wait or see a doctor

An eyebrow that rises too high, an eyelid that droops, a smile that no longer looks quite the same, or on the contrary no visible effect at all: an unexpected result after a botulinum toxin injection is worrying, and that is understandable. This guide describes the known problems, what explains them and what it is reasonable to do. It does not replace an examination by a doctor, but it helps you decide whether to wait, get back in touch with the person who injected you, or see a doctor without delay.

What can happen after an injection?

Possible problems fall into four groups, from the most common to the rarest.

Reactions at the injection site. Pain, redness, swelling, a small bruise or a firm lump are among the reactions associated with botulinum toxin injections³. They appear in the hours or days that follow and clear up on their own. Headache is also common after treatment of frown lines or forehead lines¹. These expected effects, and those that should raise concern, are covered on our page about the side effects of botulinum toxin.

An effect in the wrong place. The toxin acts on the muscles it is injected into, but it can reach a neighbouring muscle. This is what explains a drooping eyelid, an eyebrow that sits too low or, on the contrary, is raised at the tail, or a lip that moves less^1,2. These effects are almost always limited to one area: the atlas below helps you find yours.

Too little or too much effect. Sometimes nothing happens, or the effect fades very quickly; sometimes the face looks frozen. Each situation has its own causes and markers: see why botulinum toxin sometimes does not work and what to do if you feel you have had too much toxin.

Distant spread, rare but serious. Very rarely, the effect of the toxin is seen far from the injection site: muscle weakness, difficulty swallowing, speaking or breathing^1,3. The labels say that patients should seek immediate medical care if these signs appear³. That is why the box at the top of this page exists.

Identify your problem, area by area

The face is divided into eleven areas, the same as in our atlas of treatment areas. Each area has its own page, which lists the problems described and links to a detailed page for each one.

If you prefer a list, here are the eleven areas:

• Upper face: forehead problems after an injection, problems after a frown line injection, eyebrows too high, too low or uneven.
• Around the eyes: drooping or puffy eyelid, problems at the corner of the eyes and crow’s feet.
• Mid-face: nose problems after an injection, altered or asymmetric smile, lips after an injection.
• Lower face and neck: chin after an injection, jaw problems after masseter injections, neck problems and difficulty swallowing after an injection.

Why does a problem occur?

Botulinum toxin blocks the release of a chemical messenger, acetylcholine, at the junction between nerve and muscle: the injected muscle contracts less, temporarily³. A problem arises when this relaxation is not the one intended: too strong, too weak, unevenly spread between the two sides, or extended to a neighbouring muscle.

The labels themselves set out the main points of caution. They advise avoiding injections near the muscle that lifts the upper eyelid, to reduce the risk of a drooping eyelid^1,3, and avoiding the zygomaticus major muscle, which pulls up the corner of the mouth, so as not to cause the lip to droop². They also ask doctors to take into account each person’s anatomy, any previous surgery, an eyelid that already droops, or complications with previous injections³.

Some situations increase the risk of more widespread effects: a disorder of the junction between nerve and muscle, even one not yet diagnosed, or a history of swallowing problems^1,3. These are contraindications or precautions to mention to the doctor before any injection.

A problem therefore does not necessarily mean a mistake: it may be due to anatomy, to an asymmetry that was already there, or to an individual reaction. Only an examination can tell these apart.

When does a problem appear, and how long does it last?

A problem linked to the effect of the toxin appears as that effect develops. With a type A toxin, the first effects are usually seen within 2 to 3 days, and at the latest within the following week^1,4. In trials of one type A toxin, a drooping eyelid appeared a median of 9 days after treatment, and a drooping eyebrow a median of 5 days after¹. A literature review places the onset of a drooping eyelid between about day 3 and day 14⁵. With the short-acting toxin, the first effects begin 8 hours after the injection and the peak effect is seen around day 7³.

The duration follows that of the product’s effect. For type A toxins approved for aesthetic use, the effect has been shown for up to about 4 months^1,2,4, and up to 6 months for forehead lines with one product¹. For the short-acting toxin, the effect generally lasts 2 to 3 weeks³. As of 9 October 2026, this toxin is approved in the European Union (since 15 July 2026) and in Canada (since 22 June 2026)^8,9. An unwanted effect cannot, in principle, last longer than the intended effect.

There are exceptions: a series of seven patients describes drooping eyelids that persisted from 6 weeks to 13 months⁶. Such cases are rare, but they justify medical follow-up when a problem does not improve at the expected pace.

Is a problem reversible?

Yes, in the vast majority of cases. The effect wears off as the nerve terminals recover³. Experimental work shows that the nerve first forms small new branches, then the original terminals resume their activity and these branches disappear⁷. The muscle then regains its usual movement.

Most adverse effects seen in trials of one type A toxin occurred during the first week and were transient². For another, they were mostly reversible and mild to moderate⁴. The labels also note that the treated muscle is expected to waste away somewhat (atrophy) after repeated treatments³: this is worth discussing with your doctor if you have regular injections.

Can a problem after an injection be corrected?

It is best to know this from the start: the labels describe no treatment that cancels the effect of the toxin. In case of overdose, they provide for medical monitoring and supportive care adapted to the symptoms^1,3. Time therefore remains the main factor in recovery.

Some situations can nonetheless be eased. For a drooping eyelid, eye drops prescribed by a doctor can partly lift the eyelid⁵. For an asymmetry, an additional injection is sometimes considered, but only after an examination: another dose of toxin given before the effect of the previous one has worn off can make muscle weakness worse³, and type A labels generally require at least 3 months between two treatments^1,2. After a short-acting toxin, a type A toxin given less than 30 days later has not been evaluated³. The conditions under which an additional injection may be discussed are covered in our article on touch-ups after a botulinum toxin injection.

What to avoid

• Going from one practitioner to another for extra injections to "rescue" the result: another toxin injected before the effect of the previous one has worn off can make muscle weakness worse^1,3, and one label states that giving another botulinum toxin at the same time has not been studied and must be avoided³.
• Taking a medicine on your own initiative to speed up recovery: none is described in the labels for this purpose.
• Waiting silently with a warning sign (difficulty swallowing, speaking, breathing or seeing) in the hope that it will pass.
• Judging the result too early: with a type A toxin, the peak effect is only reached between week 2 and week 4, depending on the product^2,4.

Who to see, and when?

The first person to contact is usually the doctor who performed the injection. They know the injection points, the product and the dose. The labels ask for the name and batch number of the product given to be recorded³: ask for them, they will be useful to any other doctor.

Before the appointment, write down the date of the injection, the areas treated, the day the problem appeared and how it has changed. A photo taken every day, in the same light, helps you judge whether the problem is improving.

See a doctor promptly, without waiting for the follow-up appointment, if your eye becomes painful or very dry, or if your vision becomes blurred^1,2,3. Warm, painful redness spreading from an injection point may be a sign of local infection, which is among the possible reactions³. Finally, any difficulty swallowing, speaking or breathing means calling emergency services (15 or 112 in France, or your local emergency number).

If there is no effect at all, one label considers treatment to have failed when no clear improvement is seen one month after the first session; the causes should then be reviewed with the doctor¹.

The most searched problems

Four situations come up often in patients’ questions. Each has its own page, built around the same seven questions: why, when, how long, is it reversible, what can be done, what to avoid, when to see a doctor.

How this guide is written

The information in this guide comes from the summaries of product characteristics (SmPCs) published by health authorities and from peer-reviewed publications, listed at the end of the page. It describes general situations and cannot be used to make a diagnosis remotely. Each page is reviewed by a doctor before publication. For any question about your own situation, talk to the doctor who injected you or to your GP.