It might be best to take this whole thing in bite sized chunks too. Just do a general pass over the face gently nudging dials (.100 - .400) and do the whole face area, write an email look at a photo of the expression, and then come back to it after some time and do another general pass, slowly refining the look...almost like sculpting. Don't be in a hurry, study photographs.

Comitted to excellence through art.