ICD-10-CM > S00-T88 > T20-T25 > T20 > T20.7 > T20.79 T20.79 Corrosion of third degree of multiple sites of head, face, and neck Non-Billable/Non-Specific Codes T20.79XA..., initial encounterT20.79XD..., subsequent encounterT20.79XS..., sequela