If they don't call themselves out and you can prove they wiped or aren't acknowledging the hit.( adrenaline makes pain go unnoticed ) then there will (more likely than not) be a ref nearby that you can ask to perform a "paint check" which more or less means he's gonna tell you if the guy has paint on him. The only time the ref wouldn't be nearby is if you are FAR away from the action areas or if he is busy with an injured player.