Hello, I Am A Straight Male Age 21. I Recently

Hello, I am a straight male age 21. I recently noticed yesterday that I have white bumps on the bottom of my butt check, the area seems to look bruised as well. I also have a few on my butt crack. I don't think it's an STD because why would it be on my butt when I am straight and I have never done anything sexually involving my anus.