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.