My Dear Welcome to Healthcaremagic! I have noted your complaints and concerns and have arrived at the following plan of action: 1 I am concerned about your sister s health and would like to suggest certain measures keeping her circumstances in mind. 2 As long as pregnancy continues, you need not give her any medications except for topical use. The reason for this is that pregnancy itself might result in pigmentation which will last only as long until her delivery. 3 Please make sure that she stays away from sunlight, make up, or cosmetics so that any aggravation due to these causes can be avoided. 4 She might use a concealer to mask the pigmentation which will protect her from UV rays as well as give psychological boost for her worries. Once she delivers, there are several measures that can be considered like use of Hydroquinone, Kojic acid, Chemical peels, and Antioxidants. I hope with these suggestions she gets relived and eventually she should be well again. Our best wishes!