i think you did an especially nice job creating form to the nose as there is so little shading in that area naturally , where i feel the weakest part of this image was the ear as there is so much variation in shading and detail in that area, yet in your image its almost like you lost the depth and it appears as a flat object compared to the rest of the image that has great depth. as a whole id say you did an amazing job creating an accurate representation of your model. Great job!