can warfarin cause dry skin?/?

It shouldn't (dry skin is not the same as the necrosis Salubrious describes), but most people on Warfarin are older people, and the skin of older people grows drier and drier over time.

that is not a common problem

This is an excerpt from the link provided:

"Rarely, warfarin can cause the death of skin tissue (necrosis). This complication occurs most often three to eight days after you start taking warfarin. If you notice any sores, changes in skin color or temperature, or severe pain on your skin, seek immediate medical care."

Given that warning I think you should seek immediate medical attention. This doesn't mean Warfarin caused your dry skin, but it's possibly the start of something much worse, so you should have it inspected by a professional.

I don't know