ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.6 > T23.64 > T23.649 T23.649 Corrosion of second degree of unspecified multiple fingers (nail), including thumb Non-Billable/Non-Specific Codes T23.649A..., initial encounterT23.649D..., subsequent encounterT23.649S..., sequela