It’s led to mental changes, and it will last for two full weeks.

Looking now at both Ron and Harry, Dumbledore continued his explanation. “Now, I know you’ve both taken Polyjuice Potion in the past. When you did so, did your minds change at all with your bodies?” Both students shook their heads. They may have looked like Crabbe and Goyle in second year, but they had stayed themselves in their minds. Thank goodness for that as well, being stuck with their minds would have been awful. “Exactly. One of the reasons the potion is not banned is because its effects are limited in that way. But changing the recipe in the wrong way, as you did Harry, removes that barrier. Not only did you not become the person you’d been trying to, but your mind has been altered to fit your body.”

That certainly explained the stuff Harry had gotten up to since her body changed, though the sex had been good enough that it was hard to regret it. “Professor,” she began, “Could adding two ingredients really do all of that?”

But the look in Dumbledore’s eye made it clear she was still underestimating what had happened. “No, Harry. Adding one of those ingredients did all of that, namely, the Hungarian Horntail scales.” That raised a new question, one Dumbledore immediately answered. “As for the Petroleum Jelly, that had its own effect. By my estimates, the potion will last two full weeks, rather than the usual two hours.” Inclining his head towards the stairs, he continued, “In that time, you may stay with the Weasley family, if they do not mind.” Taking that as a cue to leave, Harry and Ron left the Headmaster’s Office, where they soon ran into Mr. and Mrs. Weasley. They’d heard some version of the events already, and happily took in Harry, after some quick words regarding making potions outside of school being not allowed.