The most common side effect is some slight bruising at the site of the injections, and (rarely) some people develop a headache afterward. A more serious complication of Botox injections can be ptosis, when the eyebrow and eyelid droop. This can happen when the skin is too lax or when the muscles right above the brow or the ones between them are injected. Often a slight one- or two-millimeter drop reverses within two weeks, but unfortunately the effect can last as long as the Botox results and there's no way to reverse it. There's a long list of potential side effects you should be aware of before consenting to this procedure, but most of them are extremely rare.
Find out more about this book:Simple Skin Beauty: Every Woman's Guide to a Lifetime of Healthy, Gorgeous Skin