( ah, he misunderstood. to the question, he pauses, looking thoughtful. he doesn't know if there's something specifically like what's being described but there's probably spells and incantations that can come close. )

I don't know if you would consider it a spell specifically for erasing magical deficits but if someone turns the river pink, there's going to be a spell that turns it back to its original color. That doesn't mean it erases the magic, it just...puts more magic over top of it, if that makes sense.

I don't know of an undo button for magical spells. Once something is done, it's done and unless you can control time, it stays done but it can be corrected in other ways.