This doesn't (necessarily) have anything to do with rotation speed, and the article doesn't say it does. The fact that Betelgeuse is pulsating more quickly does

This doesn't (necessarily) have anything to do with rotation speed, and the article doesn't say it does. The fact that Betelgeuse is pulsating more quickly does not imply that it is rotating more quickly. Making an entire star suddenly spin twice as fast on its axis would require a staggeringly, absurdly huge transfer of energy and angular momentum. The mass ejected from Betelgeuse was much, much smaller than the star's total mass, and would not have been capable of causing such an effect.