How does the event at the camp change the social dynamic of Auggie’s year level?

Auggie's success at the sleep-away trip with his school shows that he no longer uses home as a crutch. He feels comfortable enough with himself and his friendships to leave the security of his family and set out on his own: in a classic bildungsroman, a character's ability to leave home is a sure sign that he or she has grown up. Of course, Auggie is still a child, so he gets to return to his family once the trip is over -- though now the other Pullmans are there as support, rather than as a security blanket.

The fight in the woods is a pivotal moment in the book, to a large extent because of the way Auggie handles it. Though the kids from the other school make fun of his face, Auggie does not let such insults get to him the way he has in the past. Even more important, however, is how Henry, Miles, and Amos -- kids who had previously been on Julian's side in the "war" -- now stand up for Auggie. This is a symbolic moment, because it shows that everyone in school who matters has accepted Auggie as one of their own. Henry, Miles, and Amos, and all of the other kids in school after the retreat is over, have learned an important lesson about judging someone before you get to know him or her. In this manner, they have all grown up as much over the course of the novel as Auggie himself has.