My mother had a reaction (kumkum dermatitis) after applying a red sindoor Initially she developed white patches. After consulting a dermatologist, we used HH Lite cream as prescribed. It's been a month while using that cream Now, that white patches area has decreased but , the affected area has turned dark/black in color. There's No itching/burning currently My concern is -: Why has the skin turned black? Will this pigmentation become permanent, and is there any treatment to reverse it?