Nerissa's new legs are from Faith.
Nerissa's legs are not glamour. They're real, but expensive. See 14:05-14:16
...and they were sold to her and sewn on to her by Doctor Swineheart. That is why he won't let Snow or Bigby see Faith and lies by saying he has to run tests to keep them away. See 23:25 - 23:35
If you think I am right, or at least this got you thinking (I know it is rude to promote your own links, I apologize), check out my other thread below. I point out how Swineheart has access to everyone and is very well trusted, but should not be. I was wrong about a major prediction, as another user correctly pointed out that Colin is alive because he's in the comics. I do think he will be targeted though.
Here is one example of an obvious lie of Swineheart's that I point out. See 16:07 - 16:16.
This is just my theory. No, I am not certain of course, and I could be totally wrong. My other thread was way too long, so I thought I'd put some supporting evidence here. Thanks for reading, and especially if you look at my other thread!