Transdermal opioid intoxication has only been reported for pharmaceutical fentanyl and buprenorphine patches. Here, we report a rare case of heroin poisoning through damaged skin. A seven-year-old girl with an impaired level of consciousness and difficulty breathing was brought to a local hospital about one hour after burning with boiling water. She had a small second-degree burn on the right elbow. Clinicians were initially unable to obtain any reliable history from relatives about the cause of altered mental status. However, with a clinical suspicion of opioid poisoning, naloxone therapy started, and the patient was moderately improved. She underwent a coma workup; then she was referred to a tertiary care hospital. Further investigation revealed that after the burning, the mother left home to seek for a burn ointment from a neighbor, and the heroin-dependent father sprinkled some heroin powder over the burned area. Heroin was absorbed through the damaged skin and poisoned the child unintentionally. After three days of clinical management, the patient was discharged from the hospital in good condition without any complications. Heroin can be absorbed through damaged skin and cause poisoning. Diagnosis requires strong clinical suspicion, and an appropriate naloxone therapy may be life-saving.