Continuity mistake: When Scott turns into the wolf for the first time in his bathroom, the position of his blue coat on the toilet seat keeps changing.
Continuity mistake: At the very end, Pamela tells her boyfriend to drop dead and walks away, off to her right. But in the last shot where Scott is hugging his girlfriend and his dad, if you look just to the lower left of them, not only is Pamela still just standing there, but she's to the left of where she was standing before.
Continuity mistake: When Scott enters the dance as the Wolf, and he's walking through the crowd, you can see Chubs is right behind Mick and Pamela, and Stiles is next to Chubs. When the shot changes, Stiles is now behind Mick and Chubs isn't seen. Scott walks past Mick and Stiles and in the next shot, he hasn't passed them yet and Chubs is back behind Mick.