Do you have a concept piece you're going off of? I recommend doing quick 30min - 1hr long planar face studies. Right now the face is missing some critical plane changes, the one that stands out to me the most is the orbital inset. Asaro Head ref
Biggest thing I can see is that your skull seems to connect into the jaw, where it should come in behind the ears. And the lack of orbital inset is much more obvious without the hair. What we mean by the inset are the holes in the skull where the eyeballs sit, have a good look at bkost's references in the post above. This…
I do have a piece i am going off of, i am unsure what the orbital inset is though and the a coursery google search did not come up with anything. I have gone back and fourth with trying to do a piece that i wanted to make and straight up studies like how you are describing, the face has been the hardest thing for me to…