It seems that there is something wrong with your eyes. So, actually a lot of things could lead to swollen eyes. For example, a lack of sleep would do, eye infections would do, red eyes would do etc. Therefore, there is no point in guessing what happened to your eyes. My advice for you is to consult a doctor and take some measures before it is too late. Some eye drops are designed tackle this problem, go to a pharmacy and get some.
Swelling in the corner of your eyes could have a lot of causes, including infections of the tear ducts, the sweat glands in your eyelids or the glands that produce fluids to lubricate your eyes. And for the treatment, you can go to see your doctor, because self-care measures will not always get rid of eye swelling. Also, you can also go to get some medical attention for your treatment.
In general, such case is a phenomenon caused by keratitis. Or overusing eyes makes the orbicularis muscles of the ocular region shrink, hence blocking the opening of the gland. Also, maybe you have taken some allergic food or rub your eyes with your hands. Under such circumstances, you need to take a good rest and keep your eyes sanitary and find out the allergen.