I'm going to try to get over the fact that this picture disturbs me and give you a good review because, really, there's not too much wrong with this. In fact, it's one of the better realistic looking pictures I've seen on this forum.
Firstly, the eyebrows look too bushy and they don't seem to be long enough. Usually, eyebrows start at about the same spot the corners of the eyes do and then end right before they get to the temples. Now, considering I don't know where the temples are in this picture, I could be wrong. But even then, you could still use this for future reference.
The mouth isn't aligned correctly and the top lip isn't shaped right. To be honest, the top lip ruins the whole picture. The top lip in real-life seems to make a very soft E shape before reaching the bottom lip. And the corners of the lips are very small and shouldn't be outlined at all.
Lastly, I would like to talk about the shading. You seemed to do all right with the shading when it came to the nose, but when it came to the lines around the nose and lips, you messed it up. The shading should be in the indents instead. You could've also gotten away with shading right under the eyebrow in the duct of the eyes.
Hope this helps!