Ring Worm Big Red Bump I Have A Big Red Flat Circle On The Back Of My Arm?

I have a big red flat circle on the back of my arm? - ring worm big red bump

A couple of days, I felt a small lump on her arm and scratches. It bothered me in days, but all notices the red marker. Apartment, a circle, all the same color to bite, with no bumps on the inside, and just when I think it.Not triggered. It seems that the pictures of ringworm well. Only one aircraft red circle over a half a dollar.