Hi. I Have A 3inch Oval Shaped Rash Like Shape

Hi. I have a 3inch oval shaped rash like shape on the back of my thigh. The edges are raised and part of the oval looks like someone has colored it in. The center is light, almost like a white circle with a slight hint of an elongated x mark in the middle. I am worried. I also slept all night Wednesday through most of Thursday until about 7pm.