The good news is that with all of this painting and repainting, mixing and remixing, I figured out a skin tone mixture that I like a lot. I had always used a lot of ultramarine blue in the shadows, but for this I went heavier with more burnt umber (inspired by a documentary about Manet that I watched recently - don't know if that's what he used, but I noticed his warmer, neutral shadows).
The last thing I have to say has to do with studies and redoing a drawing or painting. I always tell my art students not to immediately write off a redo as bad or worse than the first. It will always look "different" in some way, and beginning artists often get frustrated because it does look different. Usually, when I walk away from it for a while, I come back to find that it's not as bad as I thought, and there are some things that I might like better after all. Or, I can learn something from the redo - as I did here.