Behold her

Before Mark even starts his run, he’s practically hyperventilating. What’s this? His gym crush, on the treadmill in front of him, has finally abandoned the shapeless T-shirt in favor of a form-fitting teal X-back top?
When she lifts her arms to adjust her ponytail, one of the straps moves aside, exposing a large heart-shaped mark on her right shoulder blade. Is this the reason for the ubiquitous T-shirt? Has no guy ever let his lips or fingers linger on what she probably considers a deformity? How can he ever tell her that her birthmark is, to him, a beauty mark?