Dont tip his head back hon if it happens again blood will drain down his throat and might make him throw up, tilt it forward or keep it neutral. Usually pressure on the fleshy part for 10-15 mins will sort it out if it starts over but if its a small amount it could just be that he has sneezed and ruptured something or hes been having a dig up there while you were not looking
Usually nothing to worry about in young people its one of those things and as long as it stops with pressure is fine, you can also apply ice to back of neck and forehead which helps.