Tell your son not to let up until the ref stops the match by touching him. Some kids will stop wrestling when they a refs whistle blows on a different mat, so to avoid this we tell our kids not to stop until the ref touches them. Tell your son that if a ref truly thinks the other kid is getting hurt, the ref will stop the match. If he keeps going until the ref stops the match this will avoid the "crying Wolf" tactic. I know at some point in a match, I think it is backpoints, if the ref stops the match for a kid crying of being hurt he will award your kid an extra point for the the cry baby rule. I'm not exactly sure how that works but maybe someone can shed some light on this. Wrestling is a tough sport and sometimes kids get hurt but we all know that when we get into it.