What do you mean it can't be undone?

Alan had always wondered what it was like to be a woman.

He went and visited a little old lady who was renowned to be a witch.

She gave him a bottle of potion which would allow him to become a woman for a short period of time.

She told him only to have two drop's a day.

As a little goes a long way and there would be terrible consequences if he overdosed on it.

But Alan decided to ignore her advice & use as much of it as he wanted and to hell with the consequences.

Which turned out to be not as bad as he thought it would be or so he thought until he revisited the witch who told him there was no way of reversing what he had done to himself.

Which meant he was stuck like this forever.