I've looked through all the posts in the appropriate episode tag and couldn't find it. Dean still stabs himself to get out of the dream, but it turns out that the AU was real too - the Dean belonging to the WIAWSNB-verse gets the wound and ends up in the hospital. He's with Carmen in this 'verse. Later, he gets flashes of Dean's hunting life. He even goes to a therapist and is hypnotized, and it's Hunter!Dean speaking. He and Sam also spend more time together. I remember in one chapter he and Sam were at a bank and there's a robbery, and Dean disarms one of the robbers by instinct. Later on he also starts looking into supernatural stuff, and Sam comes along, and I think they get rid of a ghost - possibly a boy that was struck by lightning or electrocuted. Missouri may or may not have been in it.