Can I use mayo, raw eggs for hydrating my skin?

Sure. Take yolk of a raw egg, add a tablespoon of (full fat not fat free) mayonnaise or yogurt (add ½ teaspoon of almond oil if using yogurt). Apply to skin and scalp lightly and let it dry. Wash it off with cold water. Or you could just by a good emollient lotion and apply it after showering, while your skin is still wet. The latter is a much easier method, in my humble opinion.