Unlucky Break

"Well..." The old lady hesitated, looking first at one of the Joannas, then at the other. Two identical pairs of eyes were looking at her pleadingly, desperately - and she shook her head sorrowfully.
"I'm sorry", she said, "but there is no way to reverse the effects of the Head Powder. Of any of my items, actually... It's not how these things work."
"WHAT?!" The two Joannas exclaimed in unison. "You can't mean-" the left Joanna began, at the same time as the right Joanna exploded, "What the-". The two heads stopped and looked at each other, almost as challenging each other to continue, and the old lady sighed.
"Look, I'm sorry, but I can't help you any longer. It's not my fault anyway: if you had been less clumsy, none of this would have happened. My advice to you is: get used to it. The magic of the Head Powder shields you from some consequences that would naturally occur otherwise, in any case." She hesitated, then nodded to herself and went on. "As it happens, I may have something you could appreciate... something that would make your future life much easier, I would wager."
"Oh yes?" Left Joanna said petulantly, placing her left hand on her hip, while right Joanna sighed with her right hand on her eyes. "And what would that be now? Another dose of powder for another head yet? Perhaps there's still space for one!" She exclaimed, acidly. The old woman shrugged.
"Not really... just a spell, as it were, that will ensure people who know you will believe you've always been two-headed. It will avoid all those unpleasant explanations about magic and Head Powder, and it comes with an added bonus: unless you explicitly make people notice you have two heads, they'll tend to take it in stride and not look at you as a freak."
"No way!" Left Joanna said. "And you just happen to have this thing with you? How convenient!"
"Enough!" Right Joanna interjected. "Let's see what the woman has, and let's go - if I'm to share this body with a newcomer, I intend to have a long discussion with that someone before anything else happens!" The old woman smiled. "Well said", she complimented right Joanna as she walked to another shelf and picked up a tiny wooden box. She opened it before the two Joannas, unveiling a silvery-looking ring, etched with delicate inscriptions. "As long as one of you wears this ring", she said, "you will be safe."