My kid, about age 12, planted her knees in gravel playing something. So she comes home and I said, Daddy will take care. However, I looked that the wounds - they were deep and tiny gravel was embedded all over. I couldn't clean it thoroughly - so I took her to the ER where they gave her local and used some kind of sterile scouring pad (made for wounds). She was bandaged for a few days and couldn't bend her knees.
I was to wait outside - and guess what - the docs and the law on the premises asked her if it was an accidnet or what.