ICD-10-CM > S00-T88 > S20-S29 > S20 > S20.1 > S20.12 > S20.121 S20.121 Blister (nonthermal) of breast, right breast Non-Billable/Non-Specific Codes S20.121A..., initial encounterS20.121D..., subsequent encounterS20.121S..., sequela