Great start on the sculpt! Likeness sculpts are, in my opinion, the hardest kind. You're not only dealing with our hard-wired recognition of human anatomy, but trying to exactly match a specific subject. No easy task!
For painting with acrylics, I like to thin down my paint with a little water (sometimes a bit of 99% alcohol) and paint in thinner washes. That way I can build up color over time, or add subtle color changes. That may work for you.