Kitano WIP on Darren 'fightpunch' Bartley concept | Am I missing something?

Hello people,

I’m working on a concept Darren Bartley did some time ago.

My goal with this was to see how much I can nail the likeness as well as stick to the concept.

I’m pretty far in and really just have the skin ‘realness’ left to do and am wondering if I missed something crucial.

Aside from that just so you know.
For the face itself, I tried to stick to photo references. For the sake of the concept, I had to shorten the jaw.
Also had to imagine the right side of the face which I’d love some input to. Will probably further refine that anyway so any ideas are more than welcome.

Different Angles and reference sheet as well as core reference.