I have had scars fade incredibly through fasting, including stretch marks which all but disappeared. Whether it would eventually completely remove a scar I don't know but it should certainly help.
Funny as it may sound sunbathing, especially while fasting, may help your skin problem as well. It may seem funny to bathe in the sun to fix a dry skin problem, but the skin has a lot to benefit from the vitamin d in sunshine at least so careful sunbathing would be necessary I think to help it find it's own healthy balance once more. Skin brushing also could assist by stimulating the skin and 'encouraging' your body to concentrate on looking after it for a while.