I've had good success with Spot-Shot taking out red stains like Jello. But now that bleach has damaged the color of the carpet, there's not much you can do. What color is the carpet? If you can get rid of the red stain (is it still there?) then maybe you could re-dye the carpet with a Ritt dye... Might be a recipe for disaster though.
I have had great luck using just plain white vinegar on a lot of carpet stains, too. With both Spot Shot and white vinegar, the method is important. Saturate the stain, then place several layers of paper towel over it, and press with your hands to absorb the moisture. Repeat, repeat, repeat. Do not scrub. Do not add water or soap.
The white vinegar has taken out doggy poo stains, cat puke stains which are really red stains from the icky dyes put in some cat foods, and a pee stain. The spot shot took out marker stains, ink stains, dirty, and rust stains. Good luck!
at 1:33 AM on Jul. 21, 2011