I pushed a cigarette onto my arm once and cut myself for a while, I think I was doing it just to see if it would be relaxing/cathartic, not really thinking about it staying long term that much in that moment, I don't think it's that bad though.
Also does circumcision count? That's a scarring of some kind, unfortunately I got no foreskin, yeah.
I also had a catheter up my dick once because I was unable to piss one night after fapping years ago, I was able to piss when I left the car right before I entered the hospital but I wanted to get it checked out anyway which was ultimately useless, one of the greatest mistakes I made, there's still kind of a red spot years later and some irritation.
This summer (I think) I also fapped pretty hard and got a little bruise from it on my dick on both sides, the skin feels harder than before, not that bad on the right side anymore though but still hasn't fully healed.