the way his ear looked after the first one, how incompetent the shooters were etc, theres lots of things flying around in comments
AfaIk, the wound on his ear was caused by a member of Secret Service, not by a glancing shot (although he claimed).
Edit: According to Wikipedia, the final stance now is that the wound was caused by a stray bullet.



















The final conclusion says, it was a stray bullet and not harsh treatment by the Secret Service.