Hi. Based on the history you have given, you should know that people with PCOS( polycystic ovarian syndrome) often have weight related issues and skin problems, so addressing that issue itself acts aa a treatment for your problem.so kindly consult a gynecologist regarding pcos treatment and management. And as far as the Dry skin is concerned- Dry skin is very uncomfortable condition associated with itching,scaling,cracking. It is caused due to various reasons. Few people have dry skin always and few develop dry skin in particular seasons usually winter. Dryness is usually more over forearm leg and face.
Causes for dryness include winter weather, harsh soaps (which will remove the natural moisturizer barrier of your skin), irritants( which could be creams u apply or clothes or ornaments) , health issues (like allergic dermatitis or psoriasis )
Treatment to dry skin includes hydrate yourself well drink plenty of fluids, avoid using harsh soaps, use cleansing lotions for face n mild soap for body , use moisturizer after showers.
It's better to consult dermatologist once if dryness is more.