Looks really good sebastianez, instantly recognizable!
Since I am a fan of this guy and the walking dead series I am going to be a little picky here.
The only problem I see so far is with the muscles underneath the eyes. If you want to make him look like him then maybe this will help:
http://www.cg-underworld.org/Bushidou/merle_draw.jpg
right now the way you sculpted the upper part you made him look much older like his face wizened, and looks a bit strange since the rest of the face doesn’t look that old
Also maybe is because of the lights, but it looks like you sculpted all the checks lines but you forgot to bring up the volumes, they look a bit to flat like no muscles underneath the skin.