Curse or jinx?
In Goblet of Fire, Chapter 37, George Weasley refers to this spell as the "Furnunculus curse" ("curse" being uncapitalized in the text), but in Pottermore, it's called the "Pimple Jinx."
I think this spell would be correctly classified as a jinx based on Pottermore being the more recent source. Additionally, since George referred to the spell by its incantation and "curse" wasn't capitalized, it's possible he forget the spell's proper name and type, rather than JKR changed her mind on the spell's type. ★ Starstuff (Owl me!) 08:00, August 22, 2011 (UTC)