There are cuticles on top layers of epidermal structure which guards skin from air.
It is said that amino acids and urea are exist in a cuticle, and they constitute a cuticle.
This natural moisturizing factor hydrates over all a cuticle. Molecule is many layered in a cuticle. Lipid molecule, such as ceramides and fatty acid, and water molecule are arranged in laminae and have a role to hold moistures of skin.
When cells have inadequate moistures by drying, cells are going to shrivel. And, keratin fibers will be condensed. Then, cuticles will lose elasticity and water molecules will hollow. Defense capability of water molecules will decline. Therefore stimulation from air can reach epidermis, and then skins get pimples and eczemas.
Lotion or toner which is with effects of moistures retention and astringent property is good for preventing skin trouble.
When you feel drying, try to apply lotion/toner few or triple times. (Repeat to apply with same drop of lotion/toner per time)