Excessive sweating (otherwise known as hyperhidrosis) can be treated by botulinum toxin. Areas commonly treated are underarms, palms of hands and soles of feet. As sweat glands are supplied by nerves, this therapy works in a. similar way to facial treatments. However, instead of reducing muscle activity and softening lines, it inactivates the sweat glands and reduces their output. Treatments last on average of six months.