Excessive sweating or hyperhidrosis is a very common problem, particularly amongst teenagers. It affects about 3% of the population, and can affect the armpits most commonly, as well as the hands, feet, scalp, face, groin and other areas. It has a big impact on quality of life, even though it is not dangerous to your health. In most cases, there is no clear cause of hyperhidrosis. There is both generalized (widespread), and more commonly localized (e.g. 1-3 areas) hyperhidrosis, of which localized is the most common and typically begins in adolescence, but sometime even in childhood and it does not occur during sleep. Some of the best treatments for localized hyperhidrosis include Botox injections, topical gels applied at night time (e.g. Hydrosal, Drysol), pills (e.g. anticholinergic such as oxybutynin), iontophoresis, and uncommonly surgery. Sometimes blood work can be helpful just to make sure there are no underlying problems such as thyroid problems or diabetes. It is best to speak with your dermatologist, experts in treating hyperhidrosis, to find out the best options for treatment for your condition.