It wasn't from the teleprompter since it's clearly intact. That doesn't mean it didn't ricochet off the stage because, as we all know, Tommy Crooks was a bad shot.
More likely is bullet hitting something and Trump took some of the splatter. Sure, he bled, but the pictures prove the wound is very minor compared to a direct hit by a 2200PFS .223....as if Tommy could make that shot even if his life depended upon it.
Iron sights? In a hurry because a cop had already seen him on the roof and he makes a One-in-a-Million shot? Unlikely.