A Face First (by Priscilla Cummings)

But the physical effects are only the beginning of her journey back. Facing a ravaged face, the need to wear a plastic face mask for at least a year, and the suspicion that her mother was at fault in the accident, Kelley begins to withdraw from the world, at first lapsing into silence, then refusing to return to school. Her mother, wracked with guilt and facing severe financial difficulties, doesn't know what to do. But her older sister, returning from France to spend the summer tutoring her, may have some ideas.

While not shying away from the grimmer aspects of Kelley's treatment, such as the peeling off of the burned skin, she does so in a delicate, careful way that shows she clearly understands what upper elementary and middle school children can handle. And she understands her characters, too. There are no nasty insensitive peers or strangers or other author tricks to cultivate the reader's sympathy for Kelley -- in fact, no villains at all. Just the long, hard slog of a loving family working their way back from disaster.