The most frustrating accident possible.
There is no remedy to a bleached out spot on a carpet other than to have a carpet installer cut this out (it’s called a carpet patch). They can replace that patch with a piece of carpet in the closet or behind the TV or couch. This is the best remedy.
Years ago we tried neutralizing the bleach with water, and then apply a carpet dye to the area and every version was worst than the prior attempts. The bleach just destroys the texture of the fabric and it prevents dyes from working as they should.
Have a carpet installer patch the area!