Curse Alleviation Charm
There was spell used in the Half-Blood Prince, performed by Severus Snape which had no name or description. He used it on Katie Bell after she was injured by the cursed necklace Malfoy gave her. Snape used this spell in order to stop the rapid spread of this curse.
This spell is only used by those prominent in the studies of the Dark Arts as if used incorrectly, the curse can spread and might even get to the person who tries to heal the afflicted.