Here is a piece I did where I used a different process on the way I work. I combined a few photographs of several facial features from different people. This would be the base of the portrait.
From there I shaped it to something different using the liquify tool in Photoshop and then started painting over it. I then proceeded painting all the skin pores on the face and painted all the other elements.
It's an exercise in trying different techniques/processes that I am still exploring at the moment.
You can see some of my work at [link]