Plot hole: Cady's plan to get revenge on Bowden includes raping and assaulting Lori. This part of the plan, however, hinges on Lori not reporting Cady to the police, which he had no way of knowing that she wouldn't. If she reported him, the investigation would have created huge problems for Cady. He bit off a chunk of her face, so the wound could have been matched to his teeth, as well the chunk of skin he bit off and spit out most likely would have had traces of his saliva on it. Not to mention evidence that could have been gathered from a rape kit and eyewitnesses that could have placed Cady at the bar with Lori beforehand (the bartender, for example). In all likelihood, he would have been arrested, tried and convicted. Lucky for him, Lori was too ashamed to report the incident.
Suggested correction: Luck didn't come into it. Cady specifically targeted her because of her connection to Bowden, and took the calculated risk that she would not want her sexual history being dragged in front of a court and all her co-workers. This ties into Cady's motive for wanting revenge on Bowden in the first place, as he had suppressed similar evidence in Cady's original case. Also, Cady is a very unhinged individual; the submitter's opinion on how sensible his actions are does not make them a plot hole.
Phaneron's point is valid. It's quite plausible that Lori would've been willing to testify. She didn't because if she did, the movie would've ended there. It's artistic license.
