Yo'
The nose looks a bit un natural, and so do the eyes, i think it would look better if one of the eyes were a different color. Perhaps instead of making plain black lines for wrinkles, perhaps you could shade the skin with a darker color version fo the skin? it might give it a more realistic wrinkle effect. overall i think the head is nice, perhaps some kind of crazy hair would go nicely in the back of the head.
~B