What could this be?

Hello, I'm 15 years old. I was at the Prater and was driving around the autodrome. Suddenly two people bumped into me. And I felt how my anus hurt extremely, as if it was starting to bleed. So I suspect my anus was overstretched. Now I wanted to go to the toilet this morning. I couldn't have a bowel movement because I had a really strange feeling. And I felt like there was something in my anus that shouldn't be there. In short: I took a photo of my anus and a part of the anus ring was swollen and there was a white, pale area on the swollen part. Can someone please tell me what I should do now or what this could be? Could it go away on its own?