I Have A Bad Rash Mainly On The Right Side

I have a bad rash mainly on the right side of my groin and it's very itchy, a bit lumpy and I seem to be sweating or oozing out a liquid from only the right side of my groin. When I wore white underwear for a day and took them off I noticed the whole right side was almost dripping from either sweat or other form of liquid. I've had this rash for months but have never done anything about it what do you think I should do and what do you think it could be.