the.com/chilblain

means A small, itchy, painful swelling on fingers or toes caused by poor circulation reacting badly to cold followed by rapid rewarming.

from A straightforward compound from Old English: 'chill' (cold) plus 'blain,' an old word for a sore, blister, or inflamed swelling. Put them together and you get exactly what it says on the tin — a cold-sore, though not the kind you get on your lip. The word 'blain' itself is ancient and mostly fossilized now, surviving in English almost solely inside this one compound.