Get emergency medical help if you have signs of an allergic reaction to Botox: hives, itching; wheezing, difficult breathing; feeling like you might pass out; swelling of your face, lips, tongue, or throat.
The botulinum toxin contained in Botox can spread to other body areas beyond where it was injected. This has caused serious life-threatening side effects in some people receiving botulinum toxin injections, even for cosmetic purposes.
Call your doctor at once if you have any of these side effects (up to several hours or several weeks after an injection):
unusual or severe muscle weakness (especially in a body area that was not injected with the medication);
loss of bladder control;
hoarse voice, trouble talking or swallowing;
drooping eyelids or eyebrows;
vision changes, eye pain, severely dry or irritated eyes (your eyes may also be more sensitive to light);
chest pain or pressure, pain spreading to your jaw or shoulder, irregular heartbeats;
pain or burning when you urinate, trouble emptying your bladder;
sore throat, cough, chest tightness, shortness of breath; or
eyelid swelling, crusting or drainage from your eyes, problems with vision.
Common Botox side effects may include:
painful or difficult urination;
headache, neck pain, back pain, pain in your arms or legs;
cold symptoms such as stuffy nose, sneezing, sore throat;
trouble swallowing;
fever, chills, body aches, flu symptoms;
increased sweating in areas other than the underarms; or
bruising, bleeding, pain, redness, or swelling where the injection was given.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Botox side effects (more detail)
