Thanks everyone!
So far she seems to be doing better: she is a lot more active than she was, even though she is (quite understandably) still hiding and still breathing hard. The rest of the dead slime coat has more or less sloughed off and some new, healthy slime is growing in its place. She's even beginning to colour up again. Hasn't quite regained her appetite: only 1 pellet every couple days, and she won't touch it unless its soft.
We're not out of the woods yet, but I find her continued survival encouraging and am grateful for her perseverance.