ICD-10-CM > S00-T88 > S00-S09 > S00 > S00.5 > S00.52 S00.52 Blister (nonthermal) of lip and oral cavity Non-Billable/Non-Specific Codes S00.521Blister (nonthermal) of lipS00.521A..., initial encounterS00.521D..., subsequent encounterS00.521S..., sequelaS00.522Blister (nonthermal) of oral cavityS00.522A..., initial encounterS00.522D..., subsequent encounterS00.522S..., sequela