Lay a tarp down underneath the stained area, then put on safety goggles and a mask to protect yourself.
Use a putty knife to scrape away the stained area of your popcorn ceiling. The entire area must be smooth, so all the texture should be scraped away.
Pin a tarp around the area you scraped. It must cover the area exactly and hang down about 4 feet.
Spray a stain blocker onto the area you scraped. Stain blockers that will spray upside down are available at home improvement stores. Allow the stain blocker to dry completely before continuing.
Spray on the texture. You can purchase a can of texture in home improvement stores. Shake it well and hold it about 9 to 14 inches away from your popcorn ceiling. When spraying the can, move your hand back and forth in a sweeping motion. Once dry, your popcorn ceiling will be repaired.