There are some difficulties posting photos on the site, they have to be only a certain amount of pixels and lately everything I've tried to post has had too many! lol
See a dermatologist. It could be a fungus, insect bites, allergy, or something else. You can test the fungus theory at home by using a cream for jock itch or athlete's foot, but I wouldn't waste the time. I'd just go see a doc. Good luck!