Unorganized content.
Healthy skin is mostly a matter of diet and hormonal balance. Far too complex for me to go into right now. Avoid industrial skin care products and polyunsaturated fatty acids.
Cold liquids (especially with ice) restricts blood vessels lining the gut, increases mucus production, and neutralizes digestive enzymes. Warm or lukewarm liquids are better for digestion and nutrient absorption.
This is supported by tradition, for instance the Chinese and the Ayurvedic.
There's also some research on it:
Try to have warm liquids with your food instead and see for yourself (but don't drink too much or you'll inhibit digestion).