carbuncle ... pus-filled excrescences on a person's face.

Not a word often used in this context in this counry-- here people have zits, and black heads and lots of other words, many of which i confess i have forgotten, (Jazz might know some-- ) i still get an occational zit-- but i remember some pretty discriptive terms (pizza faced) from my youth-- the common polite word used is a "blemish" but no one speaks of blemishes-- (except ad men) some people visit Zit city and come home with souveniers.

Acne is a large problem for teens, but most of fortunately out grow it-- except for a zit or two once a month or so, until we get old, and then can go 3 or 4 months with out an eruption. There are some aspect of getting older that are nice!

even carbuncle is not used--for a stone, but rather cabochon -- or some varient spelling. and not just for garnets, but even saphires.