Botox side effects: what is common and what is not
By The Dermatology, Laser & Vein Center
The most common Botox side effects are redness, swelling and bruising where the needle went in, plus a mild headache. Small bumps usually fade within 30 minutes and a bruise within about a week [2]. A drooping eyelid or heavy brow is uncommon, seen in 2 to 3% of patients in the label's trials, and it wears off [1]. Serious effects from toxin spreading are rare.
How does Botox cause side effects?
Botox is onabotulinumtoxinA. It blocks the release of acetylcholine, the signal a nerve uses to make a muscle contract, so the injected muscle relaxes for about 3 to 4 months [1][2]. Side effects come from two places: the needle itself, which causes redness, swelling or a bruise, and toxin reaching a muscle next to the one intended. When toxin from the frown-line area diffuses to the muscle that lifts the upper lid, the lid droops [3].
Common, uncommon and rare effects at a glance
Rates come from the BOTOX Cosmetic clinical trials in the FDA label and are given by treatment area, because the risk depends on where the injections go [1].
| How common | Typical duration | What helps | |
|---|---|---|---|
| Bruising | Common at injection sites; the label gives no separate rate [1] | About 1 week [2] | List blood thinners and supplements before treatment; makeup covers it after |
| Redness and swelling | Common at injection sites [1][2] | Small bumps usually fade within 15 to 30 minutes | Do not rub or massage the area [2] |
| Headache | 9% after forehead-line treatment [1] | Usually mild [2] | Tell us if it does not settle |
| Eyelid ptosis (drooping lid) | 3% after frown lines, 2% after forehead lines [1] | Often settles within 3 to 4 weeks [3] | Call us so a provider can examine it |
| Brow ptosis (heavy brow) | 2% after forehead lines [1] | Temporary, wears off with the toxin [2] | Call us; placement is reviewed before your next treatment |
| Eyelid swelling | 1% after crow's-feet treatment [1] | Temporary | Call us if it does not settle |
| Facial pain | 1% after frown-line treatment [1] | Temporary | Tell us at your check-in |
| Allergic reaction | Rare; reported reactions include hives, swelling and trouble breathing [1] | Needs prompt care | Seek urgent care; a known allergy to any botulinum toxin rules out treatment [1] |
| Distant spread (boxed warning) | No definitive serious reports at labeled cosmetic doses [1] | Reported hours to weeks after injection [1] | Seek immediate medical care [1] |
What raises your risk of bruising or drooping?
Blood thinners and supplements. Aspirin, clopidogrel, warfarin and other anticoagulants raise bruising risk with any injectable, as do high-dose vitamin E, ginkgo biloba and garlic supplements [4]. The same review advises against stopping a medically necessary anticoagulant for a cosmetic procedure [4]. Do not stop any medication on your own: list everything you take, including fish oil and alcohol use, and your provider decides at the consultation.
Handling the area too soon. The AAD advises against rubbing or massaging injection sites [2], and we ask you to stay upright for 4 hours so the product stays where it was placed. The full list of dos and don'ts is in our guide to Botox downtime and going back to work the same day.
Conditions on the label. Botox is not given if you are allergic to any botulinum toxin product or have an infection at the injection site [1]. People with neuromuscular disorders such as myasthenia gravis may be at higher risk of serious effects [1]. There are no adequate data on use in pregnancy or on whether Botox passes into breast milk [1], so tell us if you are pregnant, planning to be or breastfeeding.
How do we reduce side effects at your appointment?
Before any injection we go over your medications, supplements, allergies and health history, assess how your facial muscles move and mark the injection points. Dose is set to your areas, goals and muscle strength, and the injections take 10 to 20 minutes with a fine needle.
Injector experience matters for drooping. One review cites a 5.4% ptosis rate in an early FDA study, with many cases tied to inexperienced injectors, against an incidence likely under 1% for experienced ones [3]. For a first treatment we may suggest a check-in at about two weeks, when results reach full effect, to review symmetry and make small adjustments.
When should you call us or seek urgent care?
Get emergency care right away for trouble swallowing, speaking or breathing, which the boxed warning says can be life threatening, or for generalized muscle weakness or double vision [1]. These symptoms have been reported hours to weeks after injection [1].
Call our office if an eyelid or brow droops, one side looks different from the other, a bruise spreads, or a headache does not settle. If you notice blurred vision or a drooping eyelid, the label advises against driving until it resolves [1].
Sources
- [1] Allergan, an AbbVie company. BOTOX Cosmetic (onabotulinumtoxinA) for injection, prescribing information, revised 10/2024. U.S. National Library of Medicine, DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=485d9b71-6881-42c5-a620-a4360c7192ab
- [2] American Academy of Dermatology. Botulinum toxin therapy: FAQs. https://www.aad.org/public/cosmetic/wrinkles/botulinum-toxin-faqs
- [3] King M. Management of Ptosis. Journal of Clinical and Aesthetic Dermatology, 2016;9(12):E1-E4. https://jcadonline.com/aesthetic-complications-ptosis/
- [4] Hamman MS, Goldman MP. Minimizing Bruising Following Fillers and Other Cosmetic Injectables. Journal of Clinical and Aesthetic Dermatology, 2013;6(8):16-18. https://jcadonline.com/minimizing-bruising-following-fillers-and-other-cosmetic-injectables/
Common questions
What not to do after Botox?
Do not rub or massage the treated areas, and skip strenuous exercise for the rest of the day. We also ask you to stay upright for 4 hours and skip alcohol on treatment day, which helps keep bruising down.
How long is Botox downtime?
There is no downtime in the usual sense, and most patients go back to work the same day. Redness or small bumps can last 15 to 30 minutes, and an occasional bruise lasts about a week and can be covered with makeup.
How long do Botox results last?
Cosmetic results last about 3 to 4 months. They start to show in 3 to 5 days and reach full effect at about two weeks, and regular treatments keep them in place.
Does Botox for forehead lines cause drooping?
It can. In the label's forehead-line trials, 2% of patients had a heavy brow and 2% a drooping eyelid, which is why forehead lines are treated together with the frown lines between the brows. Either effect is temporary.
Can Botox side effects show up days later?
Yes. Bruising and swelling appear the same day, but a drooping lid or brow can only show once the toxin starts working, usually from day 3 to 5. The label reports spread-of-toxin symptoms from hours to weeks after injection, so new trouble swallowing, speaking or breathing at any point needs urgent care.
Botox is performed at The Dermatology, Laser & Vein Center in Cincinnati under the direction of Balvant Arora, MD, MBA, our medical director and a board-certified plastic surgeon. A consultation is the best way to find out what is realistic for your skin.
This is general information, not medical advice. Candidacy and treatment planning are determined by a licensed provider at consultation.