ICD-10-CM > S00-T88 > T20-T25 > T23 > T23.6 > T23.63 > T23.639 T23.639 Corrosion of second degree of unspecified multiple fingers (nail), not including thumb Non-Billable/Non-Specific Codes T23.639A..., initial encounterT23.639D..., subsequent encounterT23.639S..., sequela