Does jaw Botox show results quickly?

I honestly don't know when this started, but I was shocked when I took a selfie today. The jaw muscles under both ears are bulging out like I'm holding a hard candy in my mouth.

Maybe it's because I usually chew on a lot of dried squid and fish jerky, or have a habit of clenching my teeth while sleeping, but it feels incredibly hard to the touch. No matter how much shading I slather on my jaw, it doesn't hide the fact that my square jaw looks prominent from the front at all, so it really stresses me out.

I've tried using a massage roller, but it doesn't help since it's muscle. I'm worried my face will turn square if I leave it like this, so I'm thinking of getting jaw Botox.

By the way, is it very uncomfortable to chew tough food after getting this? Also, I occasionally see posts about the side effect of cheek hollowing, so I'm a bit nervous... usually, how many weeks does it take to see results?