Joe

This is my personal thought here, but I think the position of the light is wrong. The guys arm is burnt and the only part that benefits from the flash is his chin.
This may be the way you are wanting the portrait to look but my main dislike is that there is no life to the subject, his eyes look dead. There's no catch light in them and no white.
As people know on here, I am a professional portrait photographer so I know what to look for and I am afraid this image does nothing for me as it is very flat and lifeless.
Sorry to sound harsh on that but that's my views.

Paul

I'm really new to portraits so all comments are useful thanks for the feedback