maybe one of your pain meds could be replaced with a medication that has anticholinergic side effects. Along that line, scopolamine
is a potent anticholinergic and is sold over the counter
for motion sickness-- check with your doc, but a trial with a scopolamine patch might be helpful.
Finally, when the sweating starts, find a bathroom and run the water until it is real cold, and then let it run over both your hands and wrists until the sweating episode breaks.