So, based on my head studies and what I learned there, I decided to finish this piece.
I also reworked the colors in the legs and dress to make them appear rounder and not so high contrast.
It definitely looks like a better painting, at least in terms of accuracy. Unfortunately it seems to have lost any spontaneity in the figure. I kept using smaller and smaller brushes, and zooming in on my canvas. All this flies against what I've been trying to do with landscapes, probably because a sloppily rendered tree still looks like a tree, but I know this little girl and just wan't happy with the fact that it didn't look like HER.
Still it was fun, but took about 4 times as long as the usual paintings I've been doing. I think I'll try another and see if I can keep the loose qualities I like in play.