The bullet pierced his shirt for sure. And there is a force pulling the shirt collar up above his chin in an instant, it moves that much in a single frame.
Why is his entire shirt pulled upwards <30ms if the bullet exited through his neck? I very much doubt the fabric can snap back that rapidly from being pulled down. It's almost like the bullet is lifting his shirt upwards. Which is also consistent with blood spatter from the right rear side of his skull.
Headshot from below at close range? Was the scene elevated?