While I do believe Trump got shot in the ear, Trump brings a lot of skepticism onto himself in the way he addresses things, specifically the shooting in this case.
In his telling of the events surrounding the shooting, he embellished a part of the story despite there being evidence he was embellishing.
From Last Night :
when I heard a loud whizzing sound and felt something hit me really, really hard. On my right ear. I said to myself, “Wow, what was that? It can only be a bullet.”
And moved my right hand to my ear, brought it down. My hand was covered with blood. Just absolutely blood all over the place. I immediately knew it was very serious. That we were under attack.
Unless we are to believe that the Secret Service took the time to clean his hand, it is obvious that he embellished the story. In the grand scheme of things, it doesn't matter, as what matters is that someone took shots at a Presidential candidate.
However, that doesn't change the fact that when someone opens themselves up to skepticism or criticism, people are going to jump at the chance to be skeptical or critical, especially when it is someone they dislike.