Sam kept the voicemail. Of course he kept it. And he still listens to it from time to time. After the sunset, in his bed. Always when no one can hear him. He presses play, focusing on the words that spill out.
That way, he will get more pain. He will feel the burning in his eyes as he tries tp stop the tears from falling. Feel the shaking of his hands as he holds the old phone.
That way, he knows he is getting punished for his mistakes. Everything he has done.
When he wakes up at night to the nightmares of his past, he still listenes to it, never knowing it's fake. Never knowing what was the real message.
He knows the whole damn messages from the word 'Listen' to the word 'back'. He knows every single change in Dean's voice.
He tries to be strong, because he really did think that Dean was going to kill him that night. He thought that that was it. But Dean didn't and somehow...
Somehow that is even worse. It looks like Dean has forgotten the whole thing. But Sam hasn't. He thinks... He has to repay him, somehow. He owes him everything, for still being here.
Listen to me you bloodsucking freak. Dad always said I'd either have to save you or kill you. Well I'm giving you a fair warning. I'm done trying to save you. You're a monster Sam - a vampire. You're not you anymore. And there's no going back.