At some point in your life you will end up ruining something with bleach. Whether it be a shirt or your carpet its always a terrible feeling because it is irreversible. There are people out there that may be able to help you with carpet dying but sometime there’s nothing they can even do.
The only way we can help you with this is to tell you what we have found works best to cover this up and that would be chalk. Yes I said chalk. Try to find a chalk that matches your carpeting the best and either grind it up and apply it to the area or sit on your hands and knees and apply it to the spot as thoroughly as possible. Just be careful if you have white carpeting in other areas of your house that you don’t drag the chalk into there and end up dirtying another carpet.