How we cite our quotes:
It was still very early, only just past true dawn, and the water was so calm he could see his reflection. It frightened him—the face was cut and bleeding, swollen and lumpy, the hair all matted, and on his forehead a cut had healed but left the hair stuck with blood and scab. His eyes were slits in the bites and he was—somehow—covered with dirt. He slapped the water with his hand to destroy the mirror.
Ugly, he thought. Very, very ugly. (7.13-14)
This is Brian's first glimpse of himself after the plane crash, and he reacts with anger and fear. Brian's physical changes are just a beginning—wait until he gets a load of the emotional and mental changes still to come.
Outside the rain poured down, but Brian lay back, drinking syrup from the berries, dry and with the pain almost all gone, the stiffness also gone, his belly full and a good taste in his mouth.
For the first time since the crash he was not thinking of himself, of his own life. Brian was wondering if the bear was as surprised as he to find another being in the berries. (7.55-56)
This scene is a little hint of what's to come for Brian. He's already changed a bit from the boy we first met, a boy totally absorbed by thoughts of his difficult family situation. Here we see him beginning to look outward, toward the world around him. Well, toward bears, at least.
He did not know how long it took, but later he looked back on this time of crying in the corner of the dark cave and thought of it as when he learned the most important rule of survival, which was that feeling sorry for yourself didn't work. It wasn't just that it was wrong to do, or that it was considered incorrect. It was more than that—it didn't work. When he sat alone in the darkness and cried and was done, was all done with it, nothing had changed. His leg still hurt, it was still dark, he was still alone, and the self-pity had accomplished nothing. (8.12)
This is a big part of Brian's change in outlook. He's realizing that here in the woods, with no one to rely on but himself, he doesn't have the luxury of self-pity and self-absorption. Being upset about his situation isn't going to change it or make it better.