Suggest Cure For Skin Rash In The Leg & Buttock Area

I have developed a rash on my left leg and buttox region. The way i would describe the one on my leg is it is about it two by three inches long. It has a raised outside ring and a reddish irritated center. it also itches very badly. The other rash is the same thing but it is on the crack of my buttox and is slightly bigger and also itches. If you could tell me if it it needs attention that would be great