Post no. 2: This is probably interigo. It is very common in overweight people (I know from personal experience). Here's how to deal with it: Get some Sea Breeze for sensitive skin and some Aveeno oatmeal soap or body wash. Generic brands are fine. Wash with the Aveeno, dry completely and apply Sea Breeze. Caution: it will *burn* like a sonfagun, but wait it out. You should notice almost immediate relief.
Something else: interigo can also be a symptom of high blood sugar, so if it continues, do see your doctor for some bloodwork.