This looks good. I like how you've blended with very dense brush strokes. I think the highlights could be improved upon a bit with this one, though. the shoulder to the left and the collar bone should probably have a lighter highlight similar to what is applied on the face, since those are directly facing the implied light source.

First of all, this is well done. Very well done. The structure and anatomy stand out immediately and the values are well presented. I think that the only way to take this further would be to complete the lower torso. The lumbar is implied, but it feels as though the upper body doesn't have any support.