- The most common side effects of botox are pain, bruising, swelling, and dryness at the injection site.
- Less common side effects include headache, flu-like symptoms, drooping eyelids, and more.
- You should see a doctor immediately if you experience difficulty speaking or swallowing.
Botulinum toxin, more commonly known as Botox, is a neurotoxin that's most well known for its use in cosmetic settings. In fact, it's one of the most common non-surgical cosmetic treatments, with over 4.4 million procedures performed in 2020.
Botox isn't just used for aesthetics though, it's also used for medical purposes such as treating migraines, excessive sweating, and temporomandibular joint (TMJ) disorders.
However, regardless of why you're getting Botox, side effects are possible, ranging from mild ones like bruising to life-threatening allergic reactions.
Here are the side effects of botox, how to prevent them, and when to see a doctor.
The side effects of Botox
"Most side effects of Botulinum toxin are benign, transient, and localized to the injection sites," says Dr. Zeena Nawas, dermatologist and assistant professor of dermatology at Baylor College of Medicine.
Nawas says these mild side effects include:
- Localized pain at the injection sites
- Bruising at the injection sites (seen in up to 25% of patients)
- Swelling and redness at the injection sites
- Dry skin at the injection site
According to the FDA, these adverse effects most commonly occur within the week after injections, but it's possible for them to linger.
Diligently following your doctor's aftercare instructions can help reduce your risk of developing these side effects.
Nawas says some less-localized side effects include:
- Headache
- Flu-like symptoms such as fever and chills
- Asymmetry (for example, a crooked smile)
- Eyelid ptosis (drooping eyelid)
- Eyebrow ptosis (crooked or drooping eyebrow)
While you can't guarantee that you won't experience side effects like this, going to only reputable, experienced board-certified doctors can help.
When to see a doctor
You should never hesitate to contact your doctor after your Botox treatment if you have any questions or concerns.
However, some side effects are major red flags, like chest pain or difficulty breathing, and you should see a doctor ASAP if you experience these symptoms, says Dr. Desmond Shipp, a board-certified dermatologist at The Ohio State University Wexner Medical Center
On top of these, other severe and dangerous side effects are:
- Difficulty speaking
- Difficulty swallowing
- Inability to control your bladder
- Muscle weakness
- Vision problems (such as double vision)
These signs may be an indication that the toxin has spread in your body, and they can appear anywhere from hours to weeks after your injections.
In some cases, allergic reactions may occur, which can range from mild (with symptoms like redness and itching) to very rare severe life-threatening scenarios of anaphylactic shock, says Nawas. Symptoms of this include:
- Difficulty breathing
- Wheezing
- Hives
- Low blood pressure
- Nausea and vomiting
- Dizziness
- Weak, rapid pulse
"This is a medical emergency and immediate epinephrine injection is crucial," Nawas says.
How to prevent side effects
To prevent the most severe side effects like an allergic reaction, it's necessary to disclose all pre-existing allergies, medical conditions, and medications to your doctor prior to receiving Botox, says Shipp. For example, if you have an allergy to cow milk protein or a type of antibiotics called aminoglycosides, you should be very cautious or avoid Botox, Shipp says.
Your doctor will review your medical history with you and discuss whether you're a good candidate for Botox.
When it comes to preventing the less serious side effects, Shipp recommends following these aftercare tips:
- Avoid rubbing the area for 24 hours
- Avoid strenuous exercise for 24 hours
- Avoid saunas for at least four hours
- Avoid lying down for at least four hours
- Avoid medications/supplements that may increase your risk of bruising, such as:
- NSAIDs (like ibuprofen, aspirin, or naproxen)
- Biloba
- Garlic
- Ginger
- Ginkgo
- Ginseng
- Vitamin E
Insider's takeaway
Whether you're getting Botox for cosmetic or medical purposes, know that side effects are possible.
Adverse effects may be very mild and limited to the injection site, such as pain or bruising, or they can be more severe if the toxin spreads or if you have an allergic reaction.
Provide your doctor with a thorough medical history so they can determine if Botox is safe for you, and follow their aftercare instructions to lower your risk of developing adverse effects.