ICD-10-CM > S00-T88 > S00-S09 > S00 > S00.4 > S00.42 > S00.422 S00.422 Blister (nonthermal) of left ear Non-Billable/Non-Specific Codes S00.422A..., initial encounterS00.422D..., subsequent encounterS00.422S..., sequela