If you have dark bluish circles under your eyes, it's a result of seeing the color of the blood capillaries under your skin, or even the capillaries leaking blood in the area just like a bruise. Under eye skin is very thin and fragile so treat the area tenderly by not stretching or pulling which will cause damage. Products with vitamin K can help reduce the color, but be sure to keep the area very well moisturized to plump it up and keep it healthy since dry skin is thinner, more translucent and will show the color more. The thicker your skin is, the less you'll notice discoloration under the skin. Using a chemical exfoliant like AHAs over time will help thicken skin as it removes the old skin cells and replaces it with healthier skin with additional collagen. The older you get, the thinner the skin becomes, so keeping it well hydrated with creams containing rich nutrients is very important.
To camoflage the blue circles with makeup, use a little yellow concealer under your foundation. I tell my students to recall their basic art class of the color wheel when concealing unwanted spots. The complimentary colors on the color wheel when mixed together will cancel each other out-so if you have a purple spot you want to cover, using the color opposite of it on the color wheel-yellow-will cancel out the purple. Green concealers will cancel out the red of a bad blemish. And violet concealers will neutralize yellow tone spots. Just be sure to use colored concealers sparingly since using too much will result in a dark brown or ashy looking spot and take care to apply it only on the spot you want to cover and not on any surrounding skin, and always use under your foundation, not over it.
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