Red hair dye help?

Boxed dyes on already processed and damaged hair are a big no-no. The peroxide in the box dye will continue to damage your hair and they are also not designed to work on processed hair. The high lift dye you used in the first place to lift and deposit dye did so using high volume peroxide which unfortunately is highly damaging.

You'll need to cut off as much as the damaged hair as you can stand. You do no favors to yourself keeping it, you'll only lose more length in the long run as the damage travels up the strand. Next you can try to patch some of the damage with protein treatments like Joico K-pak DPR and ApHogee Two Step. These are not permanent fixes so you'll need to use them regularly until the damage has been grown out and cut off completely. Follow a protein treatment with a good silicone free moisturizing treatment like coconut oil, argan oil, olive oil.

To get your red color back use a semi/ direct dye. These will deposit color with out damaging your hair. You can also use them as often as you need to. These kind of dyes can be purchased from Beeunique.

If you want to keep staying red I recommend skipping the high lift dye and using proper bleach to do your roots. You'll be able to use a lower volume peroxide and avoid some of the damage. Also, apply coconut oil for at least an hour before bleaching and you'll have even less damage.

Everything Spooki said.

Also, just as an FYI--semi reds actually last longer than permanent reds, because the colour molecules are smaller, in addition to being much better for your hair.