Hi, whenever you are designing a creature with a human face, the anatomy of it should following real life, the volumes, rendering of the forms, and so on. Here is my overpaint, how the creature face could look if referenced to a human, having that done right, you can proeceed with stylisation and changes in anatomy that will lead to your idea.
Paintovers (1)
as
Artist's notes:
It looks flat to me, and the light and shadows are confusing.