It's Fungus or yeast infection....common around skin folds like thighs and genitals.. avoid sweating, sharing clothes,towels and soap.. specific medicine required depends on the severity.. for detailed prescription do direct online consultation by sending photos.

U r suffering from Intertrigo. It is a rash that usually affects the folds of the skin, where the skin rubs together or where it is often moist. This rubbing can cause a breakdown in the top layers of the skin, causing inflammation and a rash. The breakdown of skin makes it easier for bacteria or fungus to develop in this area. Skin folds sitting together and rubbing together causes intertrigo. This skin-on-skin friction creates a warm, moist environment. This environment invites an overgrowth of yeast, fungus, and bacteria. Effective medication is available to control the same. Consult a Dermatologist to prevent further progression of the lesions.