The trouble began, she said, when the boy asked to follow her on TikTok. The 13-year-old girl, an 8th grader at Aliso Viejo Middle School, said the request popped up on her profile in February. Her account was private, and she’d kept most of her previous followers to a small circle of friends and family. But she was familiar with the boy from being in several classes together. She hit accept. A few weeks later, the girl said, she learned that not only had the boy taken a screenshot of her from her account, but he had also used artificial...