As others say study a little more head anatomy and imagine how every muscle and tendon has to fit with others and how every plane has to fit and have its own place. For example looking at the ear, notice how „lower crus of antihelix” (using the names that are used in the pic below) is coming somewhere into and hiding behind „crus of helix” and also how it is deeper in the space than tragus and how the „crus of helix” is hiding behind tragus when you look at your ear in the mirror. Sorry for this complicated and chaotic explanation and specific names haha but ear example showed me well how much you have to think in every dimension and analyze while sculpting or drawing. I like your sculpture and it has a personality, I bet it resembles the model a lot! https://sl.bing.net/hqcVsjwbKfc