Usually, the eye bag under the eyes can be caused by lacking of sleep, genetic factor, aging as well allergic reaction. And drinking too much water before you go to bed can also cause eye bags the next day. Don't worry, you can apply cold water to massage your eyelid, it can help reduce your eye bag. Also, place a tea bag on your closed eyes can also help reduce eye bags. But if your eye bag caused by genetic factor, you may have to take eyelid surgery to reduce it. Hope this can help you.
Usually, if they are not genetic eye bags, young people will get eye bags after sleep from drinking too much water before they sleep. I can't explain why, but it's the truth. I also experience such eye bags in the morning when i wake up because of taking much of water last night. Don't worry, the eye nags will gone not long ago. If you want to reduce it, here a way that may help you: Just lay down, close your eyes, and put to a thin lemon slice on each of your eyes. Relax , and do not close your eyes too tightly, but also not open your eyes. Keep it about 15-20 minutes. Then, splash cold water to massage your eyelid. It could be work to reduce the nags under your eyes.