Scratches
Nina gets out of the tub to see scratches on her back. These are symbols that she is being overtaken by the Black Swan.
Doppelganger
Nina has a fight with her doppelganger at the end of the film. This is a symbol that she is only fighting and destroying herself.
Bleeding to Death
Nina has stabbed herself with a shard of glass and is bleeding profusely as the film ends. This is a symbol of an artist going too far in order to find perfection.
Nail Cutting
Nina constantly keeps her nails trimmed down to keep herself from scratching. This is a symbol that she has a neurotic tendency which leads to an effect upon her mental state.
Called Out
Erica has called Lincoln Center to let them know that Nina is sick and not coming. This is a symbol that she sees her daughter is losing control of who she is and she must step in to protect her.
