One of our family' friends has sweaty hands, and three years back he went to treat his hands with Botox. He was really happy after that: his hands were sweat-free after the Botox injections, and at our lunches together, he kept pestering me to go for Botox myself. I was reluctant to do so, because I don't like needles…
He, on the other hand (pun not intended!) repeated the injections when his sweaty hands hyperhidrosis returned once again, and Botox again stopped his sweating. Then, third time he went there, things didn't go so smoothly. His nerves weren't damaged by the injections themselves, but his hands felt a little numb, he said.
It turned out that he overdid it. The Botox hyperhidrosis treatment went well apparently, but maybe they used too much Botox or his system was not cleared from the previous treatment, and his hands felt numbed down for months… He said it was okay, but uncomfortable, and made writing with pen and similar tasks tricky at times.
All in all, he decided to do Botox again someday, but next time he'll make sure he only takes one Botox hyperhidrosis treatment per year. So what I'm saying is: Botox is fine, but don't overdo it!