Two days ago I found the skin on my left hand side near waist was tender. The following day it was not only tender but hurt to the touch of hands and clothes and had spread half way across stomach and down side of buttock. It is now very sore. I did find a red mark which does not look like a bite, it is ragged in shape and feels rough to the touch and pain is around that.. It seems to be spreading up side. Any Ideas?