Look at pictures of online magazins. Especially photographs of women's faces in frontview with smooth light (because there are smooth shadows ).
Something like this, here.


If you work with photoshop, add one 'plain'(german: Ebene) for the shadows and one for the highlights - so you can change the 'strengh' of shadow and highlight later through make them more or less transparent. Take a smooth paintbrush.
The shape of your model is perfect for painting on it nostrils and the root of the nose. The shadow under the nose is the darkest one.

Good luck! I like your spy! Another photograph with nostrils that might fit to your sweet spy.