When Jarek awoke the next morning, he only had one thing on his mind: taking the stone from Jasmine and using it for himself. All thoughts of changing Pearl back to normal were either secondary or even gone.
After getting dressed, he sought out Jasmine. He needed to get his hands on that stone. Unfortunately, he didn't know that "fictional" people couldn't use the stone. The only ones that could were Jasmine and the sultan.