Rewind — William Sleator

When Peter is hit by a car, he is given the ultimate do-over: go back to any point in time before that fateful moment, and alter the events leading up to his death. If he fails, he will die again--this time, for good. Now Peter's racing against time to save his own life, but what should he change? His adoptive parents don't understand him, the school jock is out to get him, and no one appreciates his own talents. This may be his last chance--can Peter cheat death, or will he be lost forever?