Continuity mistake: When Angel is talking to Cordelia in the garden at the very end of the episode "Supersymmetry" he has a cut on his cheek. The beginning of "Spin The Bottle" is the continuation of that scene, but Angel's face no longer has a cut.
More quotes from Angel
Trivia: In the opening credits there is a shot of a girl standing alone on the corner of a street. This was taken from the Buffy episode "Anne", when Buffy was staying in Los Angeles.
More questions & answers from Angel
Answer: Due to his epiphany, Angel basically had the 'true darkness' he worked so hard to reattain ripped away from him, like his soul was after sleeping with Buffy.