Most seasonal skin problems are not true allergic reactions. Instead, they are caused by a weakening of the protective power of the sebaceous membrane, making the skin unable to resist external stimuli. Combined with external stimuli from sun, wind and dust, these internal and external factors add up to make the skin sensitive. Once the skin’s stratum corneum is unhealthy, the water clotting power of the keratinocytes will become poor, and even if a lot of water is added, the water will evaporate quickly and even take away the skin’s original moisture, making it even drier. Therefore, moisturizing should not only help add water to the face, but also should take into account the repair of the keratin, so that the skin presents a healthy state, to achieve the function of defense. To achieve a healthy state of skin: 1, gentle cleaning: the change of season, it is best to change the usual habits of washing the face, reduce the number of times to wash the face. In the season of dry, fragile and sensitive skin, avoid using products with too much cleansing power to avoid damaging the natural sebum film of the skin and making the skin lose its self-defense ability. 2, strengthen moisturizing: the change of season, the temperature and humidity of the environment, will lead to poor skin metabolism, cell activity slow, need to strengthen the moisture, in order to cope with the external environmental changes. When the moisture is insufficient, the skin is prone to dryness, sensitivity, roughness, and peeling. It is best to use moisturizing skin care products immediately after washing your face and bathing to keep your skin moist. There are some sprays on the market to moisturize the water, or use a mask to moisten and wet the skin, to replenish moisture and soothe and calm the effect. After using a living water spray, you should use a cotton pad to wipe away excess water so that it does not evaporate and take away the moisture in turn. In moisturizing and nourishing products, “humectants” are usually added as a water locking function. The common moisturizers are glycerin, urea, and hyaluronic acid, collagen, etc. 3, sedation repair: Healthy skin can rely on its own natural moisturizing factors to maintain the moisturizing ability and promote the epidermal keratinocytes sound. But damaged skin, cellular moisturizing factors will be lost in large quantities, if not immediately repair the skin’s sebaceous membrane, water loss will be faster, so for damaged sensitive skin, just by replenishing moisture is not enough, need to add some repair and soothing ingredients, in order to restore the skin to health. Oats, licorice, B5, aloe vera, etc. are commonly used to repair ingredients that can improve the injured and inflamed skin, forming a protective film to promote wound healing.