my 15 year old daughter has black marks under her eyes and around her mouth. We have been to three dermatologists who all say the same thing. They also prescribe Hydroquinine to lighten the dark spots, but it burns her skin. The dosage has been lowered to accomodate her to know positive results and it has been a year now. The spots are worsening. My daughter is a person of hue. What could be the cause of her problem please?