What Is The Cause And Solution For Skin Rash In Diabetic Patient?

I have a rash under my breasts/groin/crack of my legs/now starting on my lower stomach it icthes insanely, skin hasnt broken, seems when i lay down at nite an get hot it get worse. i have been using herbal treatments such as apple cider vinegar/ drinking pau d cor tea an capsules, acidopolisis capsules, betaglucan, garlic it is getting better but slow using anit fungal cremewith tolnaftate 1 percent stops some itching up at nite from crawling itching burning when itched. I am a diabetic taking insulin oh also taking 2 tablespoons apple cider vinegar a day, i have had the rash since august under breasts just appeared, didnt itch at that time about a month it started spreading i dont know what to do i also had 2 summers ago poison sumac, really bad with allergic reaction went on iv on off for weeks then steroid pills help