"But I got him, Father! I got him as he went by and he didn't look so pretty with hives all over him, did he, Merope?"
-- Morfin Gaunt (HBP10)
Morfin Gaunt cast a spell on Tom Riddle Sr. out of spite because he knew his sister Merope was infatuated with him. The spell left Riddle covered in hives.
Possibly the same spell as the Pimple Jinx, since hives are a more old-fashioned term for pimples. However, the incantation "Furnunculus" was not mentioned so for now they are two different jinxes.