Axillary hyperhidrosis (armpit excessive sweating) as well as excessive palm sweating (palmar hyperhidrosis) are major problems, particularly in the summer. Strange as it may sound, Botox injections in the armpits and palms inhibit excessive sweating by inhibiting nervous stimulation from reaching sweat glands and giving them the signal to produce sweat. The result lasts for about 6-7 months.