I don't think He cut Himself. Given the bleeding - or rather lack thereof - after the "shot," I think He had a blood pack He smashed to His ear - and it was flesh colored. Stills make it very difficult to identify the way He seemed to be holding something in that sleight-of-hand way... Given the quantity of "blood" from the initial "impact," the fact that there was no further flow is highly suspicious.
If He had cut Himself, there would be a flow of blood for at least five minutes - at least! Likely 10 to 15 minutes, in that area. I clipped My ear once and oh My!!! Bled for a long while despite staunching and pressure.
I cannot believe that was a real injury. The data is consistent with a blood pack applied to the ear.