What you painted is awesome. But I agree with some of the other posters, it looks incomplete without the rest of his head. You could also darken the background around where his head would be (reverse-space, I think its called) which would imply that his head was there without really showing it. But really well done!
This one is of Billy . At first I thought he was just too cute to paint. Hard to not let him look like a doll as he has piercing blue eyes. Must've used every blue in my palette over and over spraying between layers. It looks just like him even if I did let the top of his head drift off....as he is so fair in colour . I used the same technique with my Joby portrait for the same reason.