We’re all a little thin-skinned (your skin at its thickest is only a few millimeters), but this multifunction organ, which covers 15 to 21 square feet, can tell you a lot about what's going on inside your body.

As a billboard for signs of premature aging, neglect, or disease, the skin can reveal that you're sleep deprived, dehydrated, if you smoke (anything), or have certain autoimmune disorders.

Chronic itchiness may be associated with lymphoma or thyroid disease.

Changes in skin color could signal liver, kidney, or heart disease.

And your skin may reveal elevated LDL cholesterol if you have small yellow bumps around your eyes and nose.

We haven't even gotten to loss of skin tone, wrinkles, age spots, or hyperpigmentation around your chest, which can signal premature aging, according to the Cleveland Clinic.

To keep your skin healthy and good-looking (and stay healthy on the inside too) enjoy a plant-based diet with no red or processed meats, excess saturated fat, added sugars, or highly processed foods.

You also need:

• 150-300 minutes weekly of physical activity (make two of those sessions strength-building)

• A good sleep routine

• The joy of a posse of friends and family, who will help replace skin-damaging stress with a smile and good blood flow

And make sure to use micronized zinc oxide sunscreen daily, drink plenty of water, and moisturize with lotions containing hyaluronic acid or glycerin.