The speaker looks back on the first time someone she cared about lied to her, and the lie involved a girl she couldn't stand. What stings most is the imbalance: he touched that girl in ways the speaker wished he'd touch her, yet he thought of the speaker as "innocently cute," nothing more. She feels both betrayed and overlooked.
The poem's mood is raw and bitter, with a quiet sting underneath. When he begged forgiveness and said he regretted it, she answered with a cold, almost clinical demand: "sanitize your whole body." It's a sharp line, a way of turning hurt into disgust and taking back some power. The ending shows that the feeling hasn't faded. She still can't bear the idea of the hands that touched the other girl touching her. The short, plain lines and sudden breaks make the poem feel like someone holding back anger, and then letting a little of it slip out.