Exercise cannot tighten your loose skin, but you can minimize the amount of loose skin you have. If you have excess skin, patience is key as you wait for your skin to adjust to your new size.
A Pepsi takes between 30 and 45 minutes to freeze solid, depending on the temperature it was at before putting it in a typical home freezer. Be aware that most (but not all) Pepsi containers will burst if you keep them frozen for more than 2 hours.
Depending on the type and size of your freezer, it generally takes anywhere from 12-24 hours for your freezer to become cold enough to keep food frozen. A good way to test this is to put an ice cube tray with fresh water into the freezer - when the ice cubes are frozen, it is cold enough to freeze your food properly. Of course, you also want to ensure you leave the freezer door shut as much as possible, so cold air doesn't escape. So resist the temptation to check it every hour from the moment you plug it in. Wait at least 6 hours before you take your first peek, but a good time frame to expect is 12-24 hours. If you have food you need to keep frozen in the meantime, a good ice chest or cooler with some blocks of ice will usually be sufficient to kee everything cold - just don't leave it in the sun or any other warm spot.