Question: how does damon come back from the dead in season 6?
Answer: As mentioned above, Elena coped with Damon's "death" by taking hallucinogenic drugs, but when that didn't work, she went to Alaric for help and asked him to compel her to forget any and all memories of Damon. Well, it worked — but then Damon had to come back from the dead and screw it all up, of course.