Not sure if perspective but there are some angles + planes that should take note.
The skull is in correct proportion except the cheek bone hangs a little low.
Note: The brow bone, that 'bulge' occurs only when the angle changes from front plane to side plane. its not a horn.
+the zygomatic bone has a nice plane to it, extending up the orbit bone
+teeth kinda goes flat then as it turns into the skull, angles up
+thers a tiny plane indent below the nose bone
+recheck the mandible
jsu a quicky paintover! try aim for planes, rather than the bone look, will help alot!