You can re-stretch your carpet yourself by using a carpet stretcher. This machine uses suction to pull the carpet fibers together, which loosens the carpet and makes it easier to remove. But if you don’t have a carpet stretcher, you can follow this process.  Place newspapers underneath and above the area that you want to stretch, then use a weight (like books or furniture) to press down on the newspapers and force the liquid out through the fibers of the carpet.