A cut in my butt crack 😳

So I have what was a scratch at the very top of my butt crack lol and I thought it was from wearing g-strings all the time and even sleeping in them. But now its gotten even worse and it's soo painful. I was looking at it in the mirror and it's even a bit white now. I know this so gross but does anyone have any idea of what it could be from? I described it to my mom and said maybe a yeast infection??