Post-emetic purpura is an often-forgotten cause of facial rash in the acute setting and can often be mistaken for more dangerous etiologies. We present a case of a child recently treated with trimethoprim/sulfamethoxazole for impetigo who demonstrated a new rash after multiple episodes of vomiting. Lab workup, in conjunction with patient history and lesion location, pointed toward a diagnosis of post-emetic purpura. Careful consideration of the history, physical examination findings, location of the lesion, and laboratory findings are essential for diagnosing post-emetic purpura and differentiating it from other etiologies acutely.