I think you have done a wonderful job. I posted pictures of my latest mask on the "works in progress" section of this site. I bend a stiff piece of wire in one continuous strand from the hairline to the transition from chin to throat. This serves as a profile gauge to work with so I don't lose the relationship between facial features and angles. I am new to carving, so I have developed several methods that work for me...
Your carving is as unique in it's representation of the female form as every individual. I wouldn't change a single thing!