Looks to me like the path in the image is heading just below his earlobe, so it wasn't the bullet that hit him in the top of his ear. There's no way he jerked his head up by more than the height of his ear in the time between it hitting him and the photo being taken.

At most it shows one of the multiple shots was very close to hitting him, if it's real. So the hit could still be shrapnel/glass from that shot or another