What Causes Painless Welt On The Groin?

Hi. I have a painless welt to the right of my groin. It is about 1" in diameter. is red on the outer edge, and the skin look like it's peeling in the center. Could it be ringworm? I don't have any other spots like this anywhere else. I do have jock itch for which I started applying ketaconazole this morning - prescribed by my physician. I noticed the welt this morning after I had visited my physician, so I don't have an opinion from him.