Keratosis pilaris. To these conditions.

White Hair or greying hair mainly occurs when your hair follicles stop producing melanin, the pigment that gives hair its color. Though, ageing is the primary reason of grey hair  but premature greying of hair in early 20’s or 30’s is now common. Genetic factors, stress, lack of nutrition, chemicals, smoking or any underlying disease like anemia can also lead to premature greying of hair. All these factors lead to underproduction melanin that leads to grey or white hair. Lack of minerals like zinc, copper is one of the most underestimated yet one of the most analysed reasons for grey hair. Turning already grey hair into black is not possible after a particular age, but you can always slow down further greying of hair. A balanced diet is the most effective solution to control greying of hair. Include lots of fresh fruits, vegetables, protein rich sources of food in your diet. Load up on food items containing antioxidant and vitamin C like gooseberry, oranges, lemon etc. Try to stay stress free, limit your on-screen time, and do exercises and yoga that will increase oxygen supply to your hair. Some cost effective hair care tips at home can also give you wonderful hair and prevent further greying - Give warm oil massage to your hair with different oils like sesame, olive oil, castor oil. Start a good hair regimen by selecting the right shampoo and conditioners. A professional hair and scalp analysis to get right hair care products for you is advisable.

As for the skin problem please see a Dermatologist personally.