29)

Some more adding and removing of edges completes the form of the nostril.

...at which point we can extrude it inwards

You can add some detail inside of the nose as well. A loop of edges will do for me here to sharpen the look.

Some more edges help form the nostrils and also take care of that 5 sided poly from before.

Let's give her some mouth, shall we? A couple of edgeloops and an inwards extrusion, created the same way the eyes were gives us a start.

The outer edgeloop forms the lips.

_

note:

I prefer to model the lips slightly parted but with teeth shut (jaws in neutral state) because it makes it easier to select the vertices of the upper and lower lips when weighting or creating morphtargets. Others prefer to model them shut because it looks more natural...that is entirely up to you.