What Causes White Circular Ring Around The Buttocks?

I just had an abortion last week and after the procedure it hurt to sit down because of my anus. I just came out the shower and took a look (it doesn't hurt anymore) and noticed a white circular ring around my butt cheeks. It doesn't itch and the pain went away at the end of last week. The first time I got this was because of a yeast infection. Help??