You have a risk of brow or eyelid ptosis (when your brow or eyelid droops because too much of the product drifted down or up in the eye area). The more qualified your injector, the lower the risk. Most side effects are caused by the person injecting you, not the Botox. Patients of experienced injectors also have a lower incidence of rash, localized numbness, headache and flu-like symptoms.