The Wooden Sea by Jonathan Carroll
What would happen if, in the middle of your life, you were to meet your seventeen-year-old self? And what if he told you had lived all wrong, but, lucky for you, he was here to help you fix it? But what if you had only a week to fix it because it just so happens you also somehow just experienced the last day of your life and the clock is ticking. What if? Frannie McCabe realises something's seriously screwy in his life when the dead dog he buried keeps turning up again. The Sciavos, a couple whose domestic war keeps the police department on their toes, disappear completely. And his teenage self arrives, full of attitude, to help Frannie sort out his mistakes - before it's too late. This is classic Carroll: engrossing, believable, surreal and compulsive: small town America as we know it really is, deep down inside.