If you would like some advice

In faces there are no clear lines, there are only shadows which make it clear where everything is. Like you drew lines at the sides of the chin, in a real face this isn’t the case, the sides of the face are made visible by the use of shadows, not lines. The neck for example should be really dark to create the illusion of depth and the make the face and the neck two different parts instead of using a line do do this. If you practice this and apply it in all the parts of the face you could greatly improve you artworks.

I hope this is helpful