Like a lot of Millennials, Sarah Curley has some tattoos. The public-health educator, who lives in Madison, Wisconsin, has a bouquet of wildflowers and the Greek word sophrosyne (meaning “temperance”) on her right wrist; some song lyrics on her ribs; and the phases of the moon on her inner left forearm. Then, there is the 3 on the back of her neck, which represents her and her two sisters. In college, she went into a tattoo shop in Eau Claire, wanting a simply crafted number. “The artist—his style was very vivid, very detailed, and kind of on the macabre side,” she told me. Still, he was the guy available that day and she was impatient. “He did a good job—I mean, it was beautifully done,” she told me. But the tattoo ended up “thicker and more ornate than I would have designed for myself.” At any other point in human history, that would have been the end of the story. Tattoos were forever. But in the past 10 years or so, tattoo removal has gone …