When given by an experienced practitioner, Botox injections for chronic migraine appear to be safe, with no known long-term side effects, says Emad Estemalik, MD, section head for headache and facial pain at the Center for Neurological Restoration at Cleveland Clinic. That said, there can be short-term side effects. “The most common one I hear is neck discomfort and weakness,” says Dr. Estemalik. “You may also experience a headache immediately after the procedure, but it usually subsides in a few days or weeks, as the treatment kicks in.” Other side effects may include pain, swelling, or bruising where the drug was injected; flu-like symptoms; watery or dry eyes; drooping of one eyelid or eyebrow; and drooling.

If you’re pregnant or nursing, you should avoid Botox injections, but they can be administered in dire circumstances. “I’ve done them when the migraines get worse and threaten the pregnancy,” says Blumenfeld. “But ordinarily, I don’t give them during pregnancy.”