For 19-year-old Sebastian Bails, fame is a full-time job. Like the YouTubers and Vine stars before him, he’s part of a growing cohort of young people finding celebrity and influence online — this time, on TikTok, a new social media platform for short-form videos. Bails considers himself one of TikTok’s cringiest creators, a brand he’s parlayed into an audience of millions. But fame comes at a price.