A really minor grazing could draw blood as seemed to happen at the first attempt, but heal within several days, which explains all the evidence I’ve seen.
Dramatically exaggerating a minor wound to maximize the benefit to him seems exactly what Trump would do in that situation.
There’s a lot more gradation in laws against actually hurting people. I’m guessing misdemeanor assault here means that an attempt was made, but maybe he punched the carrier once and the pepper spray stopped him. An aggressive threat and a fairly ineffective attack? That kinda makes sense to me