I've had a hystomecoty 12 years ago The doctor says I have like a dry skin rash on my pubic area. Also each day I find by night my knickers or panty liner is black. I wear the same brand of cotton undies I have been wearing for the past 16 years and am using the same washing powder. I have no stds and am Not having sex. Its driving me crazy cause it looks horrid and smells. Plus my public area is itchy All the time.

Any clues would be great
thx in advanced.