Well the most immediate risks would be that he cut an artery or vein. This would mean that he could possibly bleed out. There is also shock that would come into play. So the first steps would be look at where the cut is and see if you can tell by that if it did Nick an artery. If you can't tell look at the color of the blood of it is arterial blood it will be a very dark red. Apply direct and consistent pressure to the wound and pay attention to whether or not they are starting to get pale. Then either use a phone or call out for help.
