This is an UNBELIEVABLY simple spell that will reverse
your last spell. For example, if you made it rain, it will make it stop
raining.
First off, think about the last spell you cast
because this only works for your most recent spell, hex, curse, whatever
you did. Just think about the actual magick you performed, then think
about how it went wrong. This should take no more than 20 seconds AT THE
MOST. Now, say this in a clear voice in these EXACT words without
stuttering, mumbling, getting your tongue twisted, etc:
My spell went wrong,
Please reverse it.
Don't mess it up,
And don't pervert it.
SOURCE: SpellsandMagic.com