The mesh looks nice and clean, but some of the edge loops are cutting across features of the face, rather than going around them.
The basic idea of getting a clean final mesh is that you should attempt to follow edges in the object with edges in the mesh, and surround protruding or intruding topological structures. This is why you put a couple of edge loops around the mouth, and a couple around each eye, and each nostril.
However, don’t forget that these are not the only structures on the face. It is a common mistake to concentrate on these to the exclusion of any other feature, and end up with a very generic, bland, face.
Above each eye is an eyebrow ridge. Less prominent in women, but still usually there. There are the cheek bones, the muscles passing down from there and the side of the nose to the jawline, and the jaw bone itself. Under the mouth is a bump, sometimes with a dimple. All of these are equally important, and should be isolated within the mesh, so that they can be clearly defined and easily animated. Making a cheek out of what is effectively the left-off edgeloops from the eyes and nose gives you no control over its real shape.
I personally would take several of the edgeloops from round under the mouth and pass them straight down to the jawline, build an oval structure below the mouth to be the tip of the chin, build a triangular(ish) structure to form the cheekbone and muscle group under it, under each eye, and a couple of roughly rectangular regions above the eyes to be the brow ridges.
You will end up with a lot more mesh, but each structure will be easy to manipulate, and the face will be easier to model.
If you find that the person you are modelling has other noticeable bumps or hollows, then put edgeloops around them too.
High mesh density is only wrong if it serves no purpose. Adding mesh density to improve detail and accuracy is not wrong. Essentially remember that anthing that sticks in or out should be modelled by extruding it out of the original mesh. This will add the correct topology to the mesh. As a rule of thumb, you will need three times as many edgeloops as there are features on the face. This is because you need an edge at the feature, and one either side to control the shape of the crease.