3. Inflammation
Your skin acts as a barrier against the environment, and when it’s healthy, it can regulate itself accordingly (think: your skin staying hydrated on a cold, dry day). But “when makeup, dirt, and oil are left on skin, they form a film that can interfere with the skin’s ability to maintain a healthy barrier,” says Zeichner. “The barrier, known as the stratum corneum, has a brick-and-mortar model — if the skin is the brick wall, the bricks are the skin cells and the mortar is made of lipids, a natural fat. When the barrier is disrupted, there isn’t as much mortar, which allows hydration to leak out and put the skin is at greater risk for environmental exposure.” All of this leads to inflammation, which can look like redness, itchiness, peeling, scaly skin, or a hot mess mix of them all.
