As for what Cameron will look like, she has been scratched up a bit before, and her wounds seemed to heal. Maybe she has a special type of skin that can regenerate itself. I am sure they wont want to change the way she looks, I doubt she will take much damage at all.
Well, it is living flesh, so it can have basic "healing abilities", which could certainly be enhanced.
Secondly, I'm sure she's built out of the same futuristic materials that allowed Star Trek Voyager to suffer tremendous damage and still be repaired in time for the next episode without any kind of drydock or repair station.
