Hey CMC, here are some thoughts.

The nose/mouth you have isn't working, especially with the broken line at the mouth. The size you're working at makes everything very hard, so props for that.
Definitely want to add more mass to the skull. The single pixel noise and the broken outline aren't helping readability. Other than that, some minor anatomy tweaks. And shading the form. The woman will be clothed but I think her breasts could be lower. Also relaxed the pose a little. Oh also, I toned down the saturation a bit, especially in the eyes. That blue is piercing.
I'm not satisfied with my own nose/mouth combo but it's just an idea for you. I would like to see how this turns out, keep it up.