Krista Perry was at mile 18 of the Boston Marathon when she heard the murmurs that something was wrong. By mile 20, she and her fellow runners were corralled onto a side street in Newton and told that the remainder of the marathon route was closed. In the days following the attacks, her shock turned to anger and devastation. And then the 25-year-old did what hundreds of other people did to work through their grief and remember that day: She got a tattoo. In the wake of the April 15 tragedy, tattoo parlors in the Boston area were swamped with customers asking to get inked with blue and yellow ribbons, the words âBoston Strong,â and city landmarks.