Words can hurt people in many ways but can also mean thing like in the chapter where Auggie met Summer was like the best thing that ever happened to him. The words that he says were "We are like Beauty and the Beast" that is a symbol of like happiness that actually boosts Auggie's feelings and confidence. As of this Auggie still focuses on the bad things when he can focus on the positive things.
In the book, Wonder Auggie has a "relationship" with wearing masks or helmets like the astronaut helmet that he wears. Crazy things have been going on in his school and masks is a symbol for it. When Auggie wears the bleeding scream outfit it just tells you he doesn't want to be seen he wants to hide out like an owl in the daylight.