Tolerance of Cyto-selective Difluoroethane-based Cryotherapy in the Treatment of Post-inflamamatory Hyperpigmentation (PIH).

Inclusion Criteria: * Female or male. * African ethnicity * Ages 18 to 65. * Phototype V and VI according to Fitzpatrick scale * Featuring brown spots (PIH) on the back ≥ 3 mm to ≤ 6 mm in diameter (at least 4 spots per subject). * Agreeing not to be exposed to the sun (or artificial UV) during the study. * Informed, having undergone a general clinical examination attesting to his ability to participate in the study. * Having given written consent for participation in the study. * No suspicion of carcinoma after investigation by a Dermatologist. Exclusion Criteria: * Having performed cosmetic treatments (exfoliants, scrubs or self-tanners, UV ...) in the month before the start of the study, at the level of the back. * Having applied a depilatory or exfoliating product in the month prior to the start of the study, at the level of the back. * Having performed cosmetic treatments in a dermatologist (laser, Intense Pulsed Light (IPL), peeling, creams, cryotherapy ...), at the level of the back in the last 6 months. * With dermatosis, autoimmune disease, systemic, chronic or acute disease, or any other pathology that may interfere with treatment or influence the results of the study (people with diabetes or circulatory problems, allergic to cold, Raynaud's syndrome...). * Receiving treatment by general or local (dermo corticoids, corticosteroids, diuretics, anti-coagulants ...) likely to interfere with the evaluation of the parameter studied. * Participating in another study or…