Very Nice!. If you want to get all CSI on it there is some good reference material here
http://www.dipaola.org/stanford/facial/class5notes.html
Some movies of facial muscles working too if you ever plan to animate it.
I did a quick photoshop overlay of a female skull and your model looks pretty good. I would change front crown to leave some room for scalp thickness. Maybe a little too projected in middle of the face and just slightly under protruded in the chin. Bit too much space at back of head.
