Good morning, Jan and greatest job on your edges, spaces, and facial relationships on your drawing above. One issue is that some lines in some drawings are still the itchiest and scratchiest of them all. What kind of pen did you work with? A finest liner? Would you like to please work with 5 minutes of 30 second face sketches with the biggest, fattest marker you could find? As a result, your lines and relationships and such will become boldest and the most confident.
Let's hope this works out for you.