Thank you both for the comments. I've tried to adjust some of the points already:
Unfortunately due to the dark world outsite, the picture is not as good as it should be. I hope I will be able to take a better picture tomorrow.
@ AllisonR: I tried to take your comments into account. The nostril was kinda hard to do, since there is none in the picture that I used as a reference.
@ Crafor: I think it is because of the picture that the shadows seem to light, for one reason or another I am not able to make a picture that shows true contrast... The shadows are in real life almost as dark as the pupils and the dark area of the scarf (on the right for us).
The drawing is partly made from a picture (the face and hair), the rest I filled in myself.
Anyway, thank you both so much for your comments
, when I work on a drawing for a long time, I get detailblind or something.