That's what I suspect, too. I thought it looked like there was something going on with her hands back when the picture you linkedpost #4838447 was posted. Now it seems like it's not just a burn, but a gradual corruption by the Goddess of War following post #4707645 (as you yourself are commenting about there).
I wonder if that hand is an injury from when she went overboard?
Seems to be some kind of corruption as it has been advancing ever since that incident. In the beginning it only affected her fingers, but now it seems her whole hand and part of her arm are changing.