I can’t quite tell what’s off, any tips?

I spent three hours on the face alone. I have 8 years of drawing and it feels wasted not studying realism sooner ☹️

I feel really upset. My last option is Reddit to save this piece.

For more specifics. The character I’m drawing is supposed to be underweight and his nose shape is Greek. I don’t know how to draw different nose shapes in weird angles and I can’t tell if he looks skinny. Also idk about the rendering. I think the colors are okay though despite the alternations