system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why we cant just put water on dry skins?
gpt
Aesthetician here...dry skin is not just the lacking of water, but natural oils your body naturally produces. **Sudoriferous** glands (sweat glands) excrete water. Internally, adding more water and clear fluids to your diet will help improve the hydration of your skin. Externally, wash with a softer water  that is medium warm, and use a PH balanced cleanser.  **Sebaceous** glands excrete oils. Internally, add foods with good oils to your diet- olive oils, coconut oil, avocado. Externally, when washing, do not use uber hot water. It strips the skin of the natural oils that moisturize your skin. When out of shower/bath, pat skin dry and immediately apply moisturizer or coconut oil to skin. Not only does it "trap" the water on your skin, it restores the natural oils.
**TL:DR**...dry skin is lacking in both water and natural oils. Sorry the explanation isn't really ELI5.