Skin under my eyes gets swollen.

Thanks for the query. This is a common condition and is an urban life style related problem. The dark circle around the eyes at your age is unusual and could indicate an insulin resistance. Skin is the mirror of internal health and to get a perfect skin you need to treat both ways - internally and externally. See a Dermatologist who will recommend a product for reducing puffiness and darkness and will advocate the correct method to use it. Avoid rubbing the eyes as it will increase pigmentation. Your Dermatologist may request a few blood tests to understand the blood chemistry and treat them specifically. Now-a-days many chemical peels also offers realistic promise- like glycolic acid and lactic acid peels. Dermapen in combination with mesotherapy also helps. A healthy diet and lifestyle is mandatory to achieve results.