Yeah, the whole thing with Karis is that the drug basically prevents her from feeling any physical sensation (no touch, no taste, no desire of any kind, etc.); everyone thinks this is permanent just as everyone thinks drug addiction is permanent, but once Karis is able to get herself off the drug the rest turns out to eventually come back. So it's not ... quite magical healing, I guess, except inasmuch as it's unclear how much Karis being able to get herself off the drug is a result of Karis' superpowers rather than something anybody could do if they realized it was possible.

Anyway after a full book of mutual pining Karis/Zanja ends very happily and triumphantly and they rescue each other approx. 5 million times and then hook up and then ride off into the sequel and it is great! Caveats aside, that is not sarcasm. I found the relationship very satisfying.