Caroline starts from a familiar warning: adults tell us not to bully others. Her poem asks a question that rarely gets answered. What about the bullying we do to ourselves? The speaker describes a harsh inner voice that picks at her body and her flaws, asking whether she is "that fat" or "that ugly," then ordering her to stop eating and stop feeling.
The repeated "Stop!" builds into a shout in capitals, and it's hard to tell whether she is obeying the voice or begging it to quit. The poem admits that the cruelty isn't backed up by anyone else. Her friends don't call her ugly, so the attack comes only from "the person inside." The mention of scars suggests the harm may be more than emotional, though the poem doesn't spell this out.
The mood is raw, tense and exhausted. Short, blunt lines make it feel like someone confessing quickly, before she loses her nerve.