I had a similar problem, not so much excessive sweat, just really, really, rank sweat; balls, armpits, you name it. Deodorants and antiperspirants kept it down some, but when it started to smell, it was in a different class then just what you would consider B.O. It actually smelled, I guess, sickly or acidic. At the same time, I would have a nightmare trying to keep my white dress shirts from developing huge yellow stains in the pits. Again, there wasn’t A LOT of sweat, it was just nastier than I thought it should be.
Mentioned it to a doctor during a routine exam, who proceeded to lecture me about Americans and our fast food, sugar, and alcohol consumptions. It was at that point I started tuning him out. At the time I was one who enjoyed washing my after-dinner Twinkies down with a ice cold beer or four, after my 2 Quarter Pounders w/ Cheese of course. :)
What did manage to get through my shut-up-you-foreign-quack mental block was his suggestion of maintaining a proper intestinal fauna balance with live L. Acidophilus supplements, more active culture yogurt, and a/B fortified milk (Lactobacillus Acidophilus and Bifidobacterium Bifidum, which I don’t think you can get everywhere, New Englanders can find it in Oakhurst’s Nu-trish a/B milk).
Anyway, down the road I tried his suggestion, not expecting much, and it worked. It didn’t make sense to me that it would work, but it seemed to fix that problem, along with a few other seemingly unrelated problems. Many, many years later, and I’ve cut almost all processed sugar out of my diet entirely, I still remain aware of my intestinal fauna, and I have no problems at all. I don’t take a/B supplements all the time, but will add some for a while after a drinking binge, or a bout with a cold, virus, or infection, or if I end up on an antibiotic which will many times devastate your intestinal fauna along with the “bad” stuff it’s prescribed for.
It would be interesting to see if you started using some Corn Starch or Baby Powder down there to absorb as much sweat as possible, wore as much natural fiber clothing as you can to allow for breathing, and added some good fauna-building to your diet like live a/B supplements, active culture yogurt, and a/B milk if you can get it.. And see if that improves your problem at all.
Understand, that if you do have an imbalance in your fauna, it will take a while to re-grow to a healthy state, a few pills won’t do it. A few weeks is more like it (in my experience), perhaps less if you limit your intake of sugar, starch and alcohol at the same time.
I’d be really curious to see if this helps your problem.