Sorry for yet another loss.
If there no signs of tiny white spots on the rest of the fish.
No signs of flicking and rubbing. I would maybe leave redosing the tank for now.
I would lower the tank temp.
Preform a water change and gravel vac.
Keep preforming water changes till the black carbon arrives.

If there no signs of tiny white spots on the rest of the fish.
No signs of flicking and rubbing. I would maybe leave redosing the tank for now.
I would lower the tank temp.
Preform a water change and gravel vac.
Keep preforming water changes till the black carbon arrives.