Of course, dehydration can cause puffy eyes. As we know that dehydration is a condition that occurs when the loss of body fluids, mostly water, exceeds the amount that is taken in. when someone has dehydration, there are more water moving out of our cells and then out of our bodies than the amount of water we take in through drinking. In this way, our body can be disordered and in serious case, it can lead to puffy eyes. Also it results in red and blood shot eyes. So you should drink more water and eat more fruits. But on the other hand, even you have drunk a lot of water, it will take some days to recover. Generally speaking, it is about a week. So just take care of your eyes.