Cryotherapy blister on the skin of a 40-year-old woman. The blister is the result of using liquid nitrogen to freeze off a benign raised naevus (or mole). Nitrogen liquifies at -198 degrees Celsius, and this freezing kills the tissue in and around the skin lesion. This blister forms as part of the healing process, eventually becoming a scab that drops off, sometimes leaving a faint scar.
Model release available. Property release not required.