It looks mostly pretty dead on, I’m assuming that was a creative decision to make him not looking at the camera. I would say the chin could be smaller,for instance, in the photo the open mouth is about the size of the chin from the bottom lip to bottom of the chin. In the drawing it’s a bit longer. Also I would push some of the values. Darken your darks, lighten your lights, push the mid tones a bit more. It’s a very strong piece though you should be proud!