please, i start with saying i am on the autism spectrum and my words may come as annoying or even offensive to some., and I've been described as socially inept, which i agree with, because it does feel like it so I am only commenting to what I observe, and only from my own eyes: not enough but at the same time too much shadows. By that I mean, really darken the dark areas, it seems like you are using graphite pencils, I know graphite pencils can only go so dark, i know though that the blackwing pencil in matte, can go darker than this. Also, look at how dark you have drawn the eyes, and the inner ear, match that with the hair. now, what i meant by too much shadows, is that the shadows are way too long, especially the one going down her neck, you have extended it at least an inch and a half longer. that isn't as important as the one on her forehead, from the corner of the model's hair fringe, the shadows going down to her eyebrow is shorter than what you have on your work. Changing that can be important as it looks like the tilt of her head has changed from the original, which then throws off the rest of the portrait. i hope this come across as helpful, if not, just think of my reply as the ramblings of barely intelligible troll. my intentions were good. goodluck! p.s. really good drawing though, all in all

if this hand model isn't working as a professional hand model especially for Halloween, he/she is missing their calling. great hand drawing though.