Focal injections of BOTOX can effectively provide relief from chronic migraines and excessive sweating (technically called hyperhidrosis). BOTOX works by temporarily suspending the activity of the sensory nerves associated with migraines or sweat glands, depending on where it is injected. The underarm, scalp, and hands are the most common areas to get relief from unwanted perspiration. Hyperhidrosis treatments are effective for approximately 6 months and migraine treatments typically last for 3 months, after which they may be repeated for continued relief.