Not the worst I've seen, but definitely needs improvement. Add some shading on the bone part, because right now it just looks completely plain. Also, outline the teeth black, rather than that light gray color. In the picture the eyes aren't completely blue, so outline them with black, and add a black pupil in the center of the eyes. You could also add some more detail to his face around in between and right below the eyes. There is a lot of extra detail and work you could do, but right now, just work on what I said and it will be a lot better.