The energy twisted up in the scar is hot and fierce. Her healing will ease some of the pain, but it won't reduce the scar, or the damage that Ozai had done to his son. But that's okay. Zuko is used to, and resigned to, it. He would never ask anything of Katara that she didn't want to give and saving Aang with the spirit water had been far more important than removing the abuse from his face.

Eventually, he touches her hand, and gently pulls it away from his face. The redness of the eye - usually an indication that it's getting tired - is reduced, but he's still Zuko. "There's no need to tire yourself. We both know this scar is old damage. And there's not a lot anyone can do." He says softly.