HI,
I also have this problem and it really really *****! I do a lot of exfoliating. I even use a fine pumice stone to scrub the dry skin! it helps but not totally! lotions don't seem to do anything for me!
I call it my winter skin because in the summer i get so tan that you cant see it! I LOVE SUMMER! but most of the time exfoliating helps but I do it everyday because it does not go away it just lightens it for a while!
Because you have PCOS, you may also be Insulin Resistant! I am and take metformin to help this (im not on a high dose yet)
"People with a severe form of insulin resistance may have dark patches of skin, usually on the back of the neck. Sometimes people have a dark ring around their neck. Other possible sites for dark patches include elbows, knees, knuckles, and armpits. This condition is called acanthosis nigricans"
hope this helps!
I don't know, sorry. Try asking your doctor.