Wow, it looks like something oxidized her in those spots. Outside of finding a new body, I do know this. You can mix up Rit dye, I would try a small spot first. This is how you darken doll skin on the face to make it Malibu color. Use 2 parts dk. brown and one part tangerine. You might have to experiment a little with it.
I have darkened doll heads before, if I want to reroot them w/dark brown hair. I usually just cover the area I don't want darkened with plastic and then paint the liquid dye on w/o diluting it. You might have to dilute the liquid dye with a little water to get the best shade. You may have to keep working with it. Let it dry overnight, then wipe with water and apply again. I usually mix the dyes in a glass jar.
I apply it w/a Q-tip. Hope that helps.