How to Care for Succulents Through Winter and Tips for Treating Frostbite
Once a succulent suffers frostbite, the damage is irreversible, so the best approach is still to prevent frostbite from happening in the first place. Do not expose succulents to an environment around 0°C.

What to Do When Succulents Get Frostbite
1. Mild Frostbite
Some leaves of the succulent show traces of frostbite. The obvious sign is that the leaves begin to become water-soaked and shrunken, turning transparent, or even ashen.
If only some leaves show frostbite, as long as the subsequent care environment no longer trends toward 0°C (10°C is best), the succulent will have no problem surviving. The frostbitten leaves cannot recover and will sooner or later shrivel, become water-soaked, and drop off.
2. Severe Frostbite
Most of the leaves of the entire succulent, or even the stem, show traces of frostbite, with obvious water-soaked shrinking, turning transparent or even ashen and blackened.
This situation is more complicated. If only the leaves show frostbite while the stem has not turned transparent or blackened, then place the succulent in a bright, slightly ventilated environment at 10°C for about a week. During this time, do not water. Remove the obviously frostbitten leaves and observe for a while. If there is no trend toward becoming water-soaked, it can generally continue to survive and pull through. If the stem shows signs of turning transparent and softening, cut away the frostbitten stem portion completely (it must be cut away completely; if not cut cleanly, it will keep spreading upward), apply carbendazim to the wound, then set it aside to observe, and after some time do a stem cutting. If part of the stem already showed frostbite traces from the start, then directly cut away the frostbitten part and repeat the steps above.
3. The Succulent Has Been Killed by the Cold Outright
If all the leaves of the entire succulent are severely frostbitten and even the stem has become water-soaked, then you can only let your succulent rest in peace.
In short, once a succulent suffers frostbite, the damage is irreversible, so the best approach is still to prevent frostbite from happening in the first place. Do not expose succulents to an environment around 0°C.