I ve had this skin problem on my thigh which every few months fairs up as a bright purple looking mole about the size of a 5p with a red ring around the edge and dark brown uneven center. It s dissappears after a few days and looks like a small scar again. I ve been to the doctors but every time I get there, its gone down and they say it s just and insect bite but surely after about 2 years, said insect bite would have dissappeared. It s current flared up and is very painful to touch. Any advice?