ICD-10-CM > S00-T88 > S90-S99 > S90 > S90.4 > S90.42 > S90.423 S90.423 Blister (nonthermal), unspecified great toe Non-Billable/Non-Specific Codes S90.423A..., initial encounterS90.423D..., subsequent encounterS90.423S..., sequela