It took him a moment once the curse was done to realize that he wasn't in pain anymore. Because it wasn't true. The curse might have been done hurting him, but his entire body still hurt enough that it was almost hard to tell.
Looking up into the She-Carrow's face, he knew that he should just get himself off the floor and leave before it got worse. He clearly wasn't going to get any information out of her at this point, that whole prospect had entirely been blown.
But after the whole year of biting his tongue, he just didn't care anymore. So while he didn't exactly know what had possessed him, or even where on earth he'd found the strength, instead of leaving, he just glared. "...I will. But next time I do hope you remember to brush your teeth first. I daresay they're rotting."