Water/scotch stain on old popcorn ceiling

How do I remove a stain (comprised of scotch and water) on my 25-year-old whiteish popcorn ceiling? It would be difficult to paint over the 2-foot area and match the rest of the ceiling. This stain is about 2 feet long and 6 inches wide. I tried to blot a stain removal product (meant for pre-wash) gently on part of the stain, but it doesn't seem to help much, and a little popcorn comes off (not noticeable). Would you recommend trying this with bleach? Or vinegar? Any ideas would be greatly appreciated.

 

the ceiling is most likely painted with a flat paint sheen...flat paint does not clean well...popcorn ceilings do not clean well either...since you said its 25 years old...i would just use a high hiding primer and repaint...even if you get it clean..you will have a clean spot that doesnt match the rest

 

Water stains on drywall are almost always saturated thru the drywall so even with a shiny smooth surface - it can't be washed off. Use a solvent based primer. Latex primers do a poor job [sometimes temporary] of sealing stains.

Has the popcorn ceiling ever been painted? Unpainted popcorn can be problematic to paint. The moisture in latex paint can soften/disolve the texture causing it to fall off in spots. Bath rooms and areas next to windows and doors are the most prone to give you problems. Using an oil base primer over all the texture usually prevents problems. Personally I like to remove the popcorn and either skim coat for a slick finish or use a stomp or knock down texture - of course that is more work