I'm a 15 year old girl, and today I found this bump in my butt. This might sound stupid but I don't know if it's suppose to be there or not? I've looked at diagrams but I'm not sure what it is. I was constipated today and had a hard time going to the bathroom. I also masturbated today and I noticed it right after I masturbated. I'm really scared and don't know what to do? Help?