From a philosophical perspective I've always had a problem with this kind of ending. The outcome is obviously good, but it's to the effect that his surroundings perceive he no longer deserves to be bullied. Beyond this newfound incentive, nothing has changed, there is no reason to assume they wouldn't be still be at it if he hadn't gratified them. Considering the psychological horror undertones this title has (not to mention the teacher's comment) I guess that's intentional; demonstrating the right to basic human dignity is so fickle a construct.
Or maybe I'm just overthinking it. Wouldn't be the first time.