Silver RavenWolf wrote in her book "To Ride A Silver Broomstick" A great spell breaker. I'm not sure if it'll work on curses, but you can give it a try.
"If the spell has backfired (And sometimes they do) and it continues, you must break it.
Choose the first Saturday of a full moon or on the full moon its self. Use one white candle and once black candle for balance. Your props should be of a protective nature; There for, you would use a amethyst, Apache tears, or smokey quarts for gemstones.
Write a spell to undo what you have done. Be specific. For example:
On the Eve of ____
I cast a spell and
The effects I created
I must now quell.
May the spell be lifted
And Now I be gifted
specifically with ______.
Be assured that the spell does not last longer than thirty days, unless you have put a limit on it, or performed ur during a special astrological correspondences that have imbued it with a ti8me of its own."
Hope this helped