If you don't want your hand to hurt, don't hit them with your knuckles. Use the heel of the palm. Will hurt them more and you less.
sounds weird. but true?
Yeah, it's true. Would have been great to know "beforehand." But you feel super Seagall-douchy actually giving someone a heel-strike to the nose. It's like the "lift with your legs not your back" rule. It's true, but you look all faggy squatting down like that.