Another thing about the Secret Service is that even tho it's their job to protect current and former presidents, that doesn't mean they necessarily like the person they're protecting, due to personal beliefs and whatnot.
Shyt, the way they seemed soo incompetent makes you wonder if a few of them don't like Trump either, they didn't show much urgency.
Whether it was a bullet that grazed his ear or a piece of glass, the bottom line is that the bullet was meant for him, just bad aim from a nervous/shaky shooter otherwise if it was a seasoned shooter with some experience he'd be dead right now.