Zap2it has the scoop on what to expect for Elena Gilbert in the second episode of the fourth season.
“The Vampire Diaries”: One way or another, Elena does complete her transition in the first episode of the season. In episode 2, “The Memorial” — which is, by the way, one of the 5 best “Vampire Diaries” episodes ever — we’ll discover that it’s not as easy as she thought. Elena’s body begins to reject every blood source she tries (and she tries a lot). Without nourishment, she could die. Again. Also, expect to see her first compulsion as a vampire in “The Memorial” as well.
Source – Zap2it