I know this probably going to sound stupid but have you tried applying antiperspirant? My mom, when she was sweating really bad, applied the clinical strength antiperspirant under her breasts, to her butt, bikini area, bottoms of her feet and sometimes even her hands if they were sweating really bad that day.
She tried small areas at first to make sure it wouldn't bother the skin but this is what worked for her she also put a layer of Zeasorb(it's a moisture control powder) on over the antiperspirant.
On a side note hubby sweats ALOT and he's had good luck with Sweat Block. It's a wipe that keeps you from sweating. Good luck to you sorry I can't be of more help.