I saw Dallas pull up his sleeve to reveal a scar on his wrist, "I couldn't take it anymore John, I can't take the fact that she's gone."
It's been 2 months since you had last seen Dallas and the gang. Everyone is dealing with it in their own ways. Dallas has been drinking more and crying himself to sleep, Pony and Johnny have tried to help him but he always shouts "Go Away!!" At them. Soda and Darry have been staying up late some nights to talk things out with Dallas to convince him to keep faith. Two-Bit has offered to take Dal to a few bars, but all Dallas wants to do is mope. Steve has been telling Dallas that you'll be okay, you're a strong girl. But nothing could cure Dallas, not Two-Bit and his stupid jokes, not Johnny, not even Soda's smile.
But after Dal is able to finally find something, he gains hope that he'll find you. After all that was the last promise he had made, and he wasn't going to break it.