I see he is not smiling, you are marking the shadow under his lower lip. Anyway, I was thinking it might look nice with a lighter (none at all?) shadow on the outside and top of the crests and heavier / more on the inside, especially inside - bottom. You could try it at least. Looking at the reference, I think the grey part of the face could be wider (maybe make the "ears" smaller) and bring the red part down to the bottom of the crests. On the reference it looks like the red part goes all the way under the crest and is continuous with the nose.