Helen has a bath after returning from the police station, she gets out and her hair is wet. She looks at some of the slides she took, seeming to take only a minute or two to do this, and then turns off the machine. When she stands up to open the curtains, her hair is perfectly dry.
When Helen is first admitted to the mental hospital, she screams that Candyman is there. The doctor & the orderlies rush in and give her medication. When Helen & the doctor view the security camera later, the events & dialogue are out of sequence.
In order for 'Helen' to appear, someone has to say her name five times. At the end of the film, Trevor is heard saying it five times. Viewers may incorrectly thought he said it only four times, since the time gaps between his saying 'Helen' was quite large due to the interference of his crying scenes and Stacey's kitchen scenes.
When Helen is clicking through slides after taking a bath, she views two slides of the painting of Candyman's face with the hole in the mouth. Earlier in the movie, she had run out of film before entering that room. However, she is later seen going back to take pictures of it; this is right before she meets the little boy, Jake.
The goof items below may give away important plot points.
When Helen goes back to save the baby, she opens the medicine cabinet which is about a foot and 1/2 wide and 2 feet long, but when the camera shoots Helen from behind just as she enters the opening, the cabinet opening is much wider and longer almost window size.
When the Candyman breaks the window to escape the psychiatrist's office at the hospital, there are shards of glass in the frame. In subsequent shots, when Helen goes to the window, all of the glass has been cleared.
After Bernadette is killed and Helen is in the hospital seeing Candyman the nurse says "Get me 1000 MLs". 1000 MLs is a liter - that volume is way to large for an IV injection on a human for any sedation drug.
When Helen shows Bernadette how the killer comes through the mirror, she has no shelves or objects in her medicine cabinet. This is because Helen has prepared everything to show her Bernadette, even being clear that there next apartment was vacant. Later, when Candyman hits it out with his hook, it has shelves full of objects, objects which Helen would have replaced after her show and tell.