Creating the Nostrils and Lips

First the nostrils were created by using the connect edges tool to subdivide the edges around the nose into more sections so the turbo smooth modifier was act more harshly around this area of the nose. The create tool was then used to create a polygon to fill in the nostril area that was missing and finally the extrude tool was used to lift the nostrils up into the nose. The area around the nose was then altered slightly in order to give a more natural appearance.

The lower lip was created by highlighting the edges on the mouth edge of the mesh and holding Shift + Left Mouse to create extra geometry connected to the lip area. Doing this a couple of times created enough polygons to be able to manipulate the vertices into the shape of the lips. The same was then repeated for the upper lip.