Awesome work! Looks pretty smooth. The blending on the entire face looks pretty damn good. You should definitely do some hair study though. While the highlights on your hair are great, the hair seem to lack shadow.

If you look at the flat brown at the back of the hair, that is your base colour. If you look at the front, that's where you made highlights and then blended them into the base colour. Make shadows darker than the base colour or as a multiply layer with transparent dark cool colour if you want that kind of effect.

I can see the linework through the paint on the shirt and hair. It looks very good on the shirt. It adds a good amount of depth. But on the hair it doesn't look that good. Instead of adding texture, it just looks like someone lightly scribbled on a photo. You can try using a textured brush, they have some for fur and hair and using light stokes to make directional texture.