It may hurt more when he gets older. Or he could just tag a more sensitive spot next time...or an area that bleeds more readily. There are an awful lot of stories about folks that get tagged by their little bp's and end up bleeding like crazy. Nothing that'll do any lasting harm, of course...but still messy and inconvenient and probably painful. Also, tagging you can cause injury to their mouths if you reflexively jerk your hand away.