Most people see their lines begin to soften three to seven days after treatment, and the effect keeps building for up to two weeks. That is the most useful thing to know about this stretch of time: day four is not your result, day fourteen is. Injection bumps flatten within an hour or two, and bruising, when it happens, usually fades inside about a week. Call your injector if one brow sits noticeably lower than the other or an eyelid starts to droop. Get emergency care for trouble swallowing, speaking or breathing.
The onset curve, day by day
Botulinum toxin does not work on contact. It has to reach the nerve endings at the muscle and interrupt the signal telling that muscle to contract, and that takes days rather than minutes.
The first few hours. Small raised bumps at each injection point are expected and settle quickly. You can wear makeup, but the American Academy of Dermatology advises not to rub or press the treated areas and to wait two hours before strenuous exercise.
Days one to three. Some people feel a lightness in the forehead, or a slightly heavy brow. Others feel nothing at all. Both are normal, and neither predicts your final result.
Days three to seven. This is where most of the change shows up. The AAD reports that most people see results within three to seven days.
Days seven to fourteen. The effect continues to deepen. A published review of botulinum toxin type A for frown lines describes onset of action occurring anywhere from three days to two weeks after injection. Small asymmetries visible on day five very often even out on their own by day twelve, which is exactly why we do not touch them on day five.
Why the two week review exists
A two week follow up is not an upsell and it is not an admission that something went wrong. It is the first point at which we are looking at a settled result rather than a moving one.
At that visit we check three things. Is the movement reduced where you wanted it reduced. Is the result even side to side. Are there muscles now working harder to compensate, which is common in the brow when the forehead is relaxed. If a small adjustment is warranted, that is the appointment to make it, because adding product before the first treatment has fully expressed itself risks overtreating an area that was going to settle anyway.
If you are new to this, our guide to preventative treatment covers how the timing decision differs when you are treating lines that are not yet fixed in place.
What normal bruising looks like
Bruising is the most common thing patients call about, and usually the least concerning. The AAD lists swelling, redness, soreness and bruising among expected effects, with bruising lasting roughly a week. Expert consensus guidance suggests that brief cold pack application after injection helps limit swelling and bruising, and that anticoagulants and anti-inflammatories raise bruising risk without being reasons to avoid treatment.
Never stop a prescribed blood thinner for a cosmetic appointment. That decision belongs to the clinician who prescribed it, not to your injector and not to you.
Normal bruising is flat, changes colour over days, and is confined to the injection area. Bruising that spreads well beyond where the needle went, keeps enlarging after the first day, or comes with significant pain is worth a phone call.
The aftercare rules, and which ones the evidence actually supports
Here is the honest version. The short list with the widest professional agreement is: do not rub or massage the treated areas, do not press makeup in, and hold off on strenuous exercise for a couple of hours.
The longer list you will find on social media, do not lie down for four hours, do not fly, do not wear a hat, do not drink alcohol for a week, comes largely from custom, caution and manufacturer guidance rather than from randomised trials. Following them costs you almost nothing, so there is no harm in doing so. But if you accidentally broke one, you have probably not ruined your result, and you should not spend two weeks anxious about it.
What is not normal, and what to do about it
A drooping upper eyelid is uncommon but real. Consensus literature places treatment related eyelid droop at roughly two to three percent of aesthetic treatments, with brow droop in a similar range. A review of complication management notes that toxin related eyelid droop typically appears within the first seven to ten days and resolves within two to four weeks, and that prescription alpha agonist eye drops can lift the lid a millimetre or two while the muscle recovers. That is a prescription decision, so call the clinic.
The limitation worth stating plainly: there is no way to reverse botulinum toxin. Drops and time are the tools available. Anyone promising to undo it is selling you something.
Red flags that mean stop and seek care
The FDA label for onabotulinumtoxinA carries a boxed warning that toxin effects may spread from the injection site, with symptoms reported hours to weeks after treatment. No definitive serious spread events have been reported at the labelled cosmetic doses, but the warning is there for a reason and you should know the signs.
Seek urgent medical care for any of the following, at any point in the two weeks:
- Difficulty swallowing, breathing or speaking
- Double or blurred vision, or a change in how your eyelids open
- Generalised muscle weakness, or weakness in the neck
- Signs of infection at an injection site, meaning spreading redness, warmth, pus or fever
- Sudden severe pain, skin blanching or mottling near an injection site
After the two weeks
Once the result has settled, expect it to hold for a stretch. The AAD puts duration at about three to four months and sometimes longer, and the published literature commonly reports three to six months. Rebooking before the movement returns is a reasonable plan. Chasing a shorter interval than that is not, and it is worth asking why an injector suggests one.
If you are weighing what this treatment can and cannot do for a particular line, our comparison of relaxers and fillers sorts out which problem each one solves. You can also read more about our approach on the aesthetics service page.
Medically reviewed by Krishna Borges, MSN, APRN, FNP-C. This article is for general education and is not a substitute for individual medical advice.