This is the progress after the 3rd day of work. The lips are almost finished - more darks and lifting of highlights will come later. Also, the modelling around the mouth will be done - these shadows will go a long way to achieve a likeness.
Now, I am working on the skin tones. I've started to model the nose and am building up layers on the face, modelling as I go. There are 4 basic layers on the skin, at this stage, and I am just beginning to use pink and orange hues to model the contours of the face. Later, I will use a soft violet and increasingly darker tones to gradually create depth and translucency.