We don't grow Heuchera's in pots any more (or Heucheralle/Tierella), as they always succumb to Weevil. The do far better in the ground. Personally, I pick the grubs out of any soil and throw it on the garden, but I never re-use it in a pot.
If there is any life at all in the heuchera you could try washing what remains and starting again as a cutting. You will need to be careful as the eggs are soil colour.
@NewGardenerCornwall That is what I thought might be the case from your photo. Always worth thinking of if it should happen again it is possible to rescue them if you are careful.