ICD-10-CM > S00-T88 > S00-S09 > S00 > S00.4 > S00.42 S00.42 Blister (nonthermal) of ear Non-Billable/Non-Specific Codes S00.421Blister (nonthermal) of right earS00.421A..., initial encounterS00.421D..., subsequent encounterS00.421S..., sequelaS00.422Blister (nonthermal) of left earS00.422A..., initial encounterS00.422D..., subsequent encounterS00.422S..., sequelaS00.429Blister (nonthermal) of unspecified earS00.429A..., initial encounterS00.429D..., subsequent encounterS00.429S..., sequela