Pre-approval treatment retroactive coverage: ① keep all medical records and receipts, ② industrial accident approval can take 1–3 months, ③ once approved, eligible costs reimbursed retroactively, ④ continue treatment during approval process, ⑤ Korean medicine treatment also eligible. Don't delay seeking treatment while waiting for approval — your health takes priority. Submit all documentation when approval comes through. Workers compensation labor counselors can help with paperwork.