You can use the cosmetics to make a fake swollen eye. I have the same experience like you. And i just start learning how to make up when i was young. At that time can not use the cosmetics well and use the eye shadow which the color is pink or red to skin under my eyes. So when i go outside happily was asked by some friends why my eyes are swollen. At that time know how to make the fake swollen eyes. And you can try to use different colors, and there will also have different effect. Maybe you can make a fake black eye if you use the dark greenish color.
With my own experience, I think you can drink a lot of water last night before going to bed. Then you will get swollen eyes when get up in the morning next day. Or you can drinking alcohol or salty or spicy foods before going to bed, or hormonal changes. Moreover, if you are good at makeup, you also can use make-ups to make a fake swollen eyes. Hope this helpful.
I just wonder why you do that? It is abusing action to yourself. If you don't want to go your aunt's house, just tell your mom. Anyway, if you really want to make a fake swollen eyes, you can punch your eyes your self. Besides, you can also make up with some eyeshadow. Or just use onion to make your eyes irritated. But i don't think those are good ideas. You shall think it twice before you think.
I have one swollen eye that is irritated right now and I am trying to make the other one swollen so it looks a little even so at the moment I am trying, rubbing it, 'accidentally' opening my eyes when washing my hair with shampoo and all those little things