i would hit him with a red-brown dust in the shadows, and some spots. i also would change your light to cold (urine-colored) light. I also kicked up the red in your shadows to give it that translucent ugliness
heres a very dramatic recoloring:



you dont have to be that drastic, im just throwing the ideas out there.
not on the edit - i would put a little more of his chest in shadow, it feels like you bring the light in a little bit high, considering the shape of his arm, and surely it isnt sticking out farther??