I watched a TV Program where a celebrity said she injected botox @ her armpit because it sweats. But after some time she noticed that sweat starts coming out heavily on her palm and the area between mouth & nose. According to the doctor (that she consulted afterwards), the sweat gotta come out somehow and since she blocked it on her armpits, the body uses another channel to release the sweat.

I'm not sure of the accuracy and it may vary case by case. You might want to check on this before going for the surgery. I do get sweaty palms at times and it's troublesome when I need to shake hands with people. But I guess it's not so serious that I actually thought of surgery... Hope the stuffs described above gives you some insight.