An impact from a blunt object like a bullet would absolutely show damage, and clipping an ear would have to take a piece off.

If it was clipped by a sharp piece of broken glass or plastic it might, because cuts from sharp objects can bleed a lot but be pressed together and heal pretty well. My wife cut her finger on broken glass last week and it bled like crazy at first, but with a little pressure and a bandage for a couple of days you could barely tell it ever happened.

Trump was nicked by some shrapnel and played it up as being hit by the bullet for his base.