Jon immediately began regretting his wish. He realized everything that could go wrong with a random wish with him as the victim. He was thinking with his dick at the time but his brain had finally caught up and was sending a red alert. He also realized he hadn't included a condition in his last wish to revert it. Panicking a little, he tried to wish a fail-safe, but something completely different came out of his mouth.
"I wish someone I know and who know me would get a power able to change everything about me except my mind." Jon's eyes widened after hearing what he said, but he couldn't stop himself. "This power will not be straight-forward and would have condition restricting it, but the person who inherits it will know everything about it. And any change brought by it can only be reversed by that same power" Jon tried dropping the stone but it was like it was glued to his hand. "I wish that the person getting that power wouldn't hesitate to use it and won't wonder were it came from. I also wish this power cannot be altered or removed and that the one who receive it will keep it until his or her death."
As his voice stopped, Jon was filled with dread about what he just said. His first thought was to try to mitigate the damages with the stone, but his voice didn't obey him, once more. "Finally, I wish the wishing stone would disappear for a month, after which it would come back in my possession."
And with that, the stone vanished, leaving Jon's hand empty.
He stayed unmoving for a few minutes, processing what just happened. He had given someone powers over him that could change his life forever and he didn't know who or what. The stone was gone for a month and even if he still had it, he wouldn't be able to wish away whatever changes would happen to him. If this power ended up with someone who hated him, it could be really bad for him.
He tried reassuring himself that at least, his mind was safe, but he could only accept the reality...
He was screwed.
After what felt like an eternity and an instant at the same time, Jon got up and left his bathroom, going back in his room.
Whoever the wish had picked, he could only wait to find out.