http://www.medicinenet.com/hyperhidrosis/page2.htm
Botulinum toxin (Botox), a muscle poison much in the news as a cosmetic treatment for wrinkles, has actually been used in many areas of medicine for some time, such as in the treatment of muscle spasms, and certain types of headaches. Its latest medical niche is the treatment of excessive underarm sweating.
Fifty (50) units of Botox are injected into roughly 20 spots in each armpit. This may produce approximately six months of relief from sweating. The injections are uncomfortable, but use of a very small injection needle makes them tolerable.
Now that this treatment has received FDA approval, many health insurers are providing coverage for the injections and the Botox itself, which is quite costly.
Currently, the FDA has not approved Botox for treating sweating of the palms and soles of the feet, though some physicians are administering it as an off-label use, reportedly with success. Palm injections cause more pain, requiring nerve blocks to numb the hands in order to make the injections comfortable.