Tattoos are supposed to be permanent and personal. But what happens when you outgrow them?

There’s no magic eraser for life’s messy canvas, as 22-year-old Charlotte Ahern could tell you firsthand if she wasn’t holding her breath through the pain.Once a month, Ms. Ahern sits in a dentist-type chair, dons protective glasses and cranks the volume on her noise-cancelling headphones, usually to Pink Floyd’s The Great Gig In the Sky.