Patience is a virtue, one that you so very clearly lacked. Of course John's apprentice just had to go behind his back and practice complicated spells on their own, what you had claimed to be practicing was a spell that would help plants grow. What you actually did however was de-age yourself to the age of about five or six. Which was a problem because one, John didn't particularly like children. And two, now his apprentice was back to elementary school age.
You'd looked through every spellbook that John had to try and find a solution, but found nothing. John sighed, pinching the bridge of his nose"I suppose we'll just have to wait it out then, yer not advanced enough for this sorta thing to be permanent anyways. What'll this last us, a couple days at most?"
And so now you had to spend the next couple of days to possible weeks as a small child, John had to take you everywhere with him now because he no longer trusted you alone in the flat with spellbooks. As the two of you walked around the streets of liverpool shopping for groceries and other necessities John tried his best to seem at least mildly interested in whatever you were saying.
It would cause unwanted attention from others if he snapped at you to just shut your gob already, so he simply just tried to tune you out while also looking like you were paying attention. As you stopped in front of a bakery John knelt down in front of you and whispered,"Listen here, if you behave the rest of this trip i'll buy you something from the sweet shop. Deal?"