Continuity mistake: When Tommy collapses on the stage he is facing Carrie, but when Carrie tries to cradle Tommy, he is facing the backdrop.
Continuity mistake: The stain from Carrie's bloody hand on the PE teacher's skirt switches from a smudge in the shower room scene to a full hand-print stain in the principal's office. The stain is also higher on the skirt from where Carrie originally grabbed it.
Continuity mistake: At the beginning of the movie Margaret White gives birth to Carrie. She gets a pair of scissors out of a drawer and tries to stab Carrie in the face. When Carrie starts to cry Margaret picks her up and holds her near her face and the umbilical cord has disappeared. It was there before she picked Carrie up, and she never cut it.
Continuity mistake: Chris' mobile phone video of Carrie in the locker room is inconsistent with the event as originally shown when it is projected at the prom to humiliate Carrie. Carrie's cries for help don't occur in the same places that they originally did, and some of them are from before Chris started recording.
Continuity mistake: Carrie still has her shoes until she lands outside where she's suddenly barefoot, then she seems to have them back walking home.
Answer: Sue just woke up from a terrifying nightmare in which Carrie's arm reaches out of her grave and grabs Sue. A lot of hospitals have crosses in the rooms. It's been suggested that Sue might have miscarried and lost her baby.