Cold sore or what ??

I’m doing this anonymously because it’s embarrassing! What is this on my little mans lip!? Is it a cold sore ? I have no clue what else it could be ! I don’t allow people to kiss my kids on the mouth and i have never had a cold sore before so it couldn’t be from me . Or does it look like something else ? I thought he banged his mouth but it got worse.

(don’t mind his dirty mouth typical boy always a mess!)