Everybody's so fucking neurotic. Like, 'Oh shit, if she sees that he stole her panty liner his life is literally over.' Calm down. If she tells everyone or shows the video around, then it's gonna be embarrassing for him, but that's also embarrassing for her. Realistically, the most likely outcome is she just stops stops talking to him and leaving her period pads in the bathroom trash and they both move on. Since this is fiction, she probably confronts him about it and, depending what kind of story we're getting, he freaks out and spirals, or she turns out to be a secret degenerate and they connect over it.