Neither of us are working with any evidence, but I find it highly unlikely that the bullet first impacted some other medium of metal, glass, or wood before reaching the target given the line of sight between the shooter & Trump. Another medium fragmenting and causing damage to a target is referred to as spalling.
The most logical explanation is a bullet directly impacted his ear. The alternative is that the bullet flew past Trump, hit a sufficiently hard and dense material, and that caused the bullet to ricochet back striking Trump in the ear.
As mentioned, it really doesn’t matter. Trump narrowly escaped death and was injured in the assassination attempt. Your posting history, intentionally or not, seems to downplay the gravity of danger to Trump and the existence of an injury to his ear.