I'm planning to get Botox for my square jaw.

I've had a square jaw since I was young, so I'm writing this because I really want to do something about it now. I know my bone structure is big to begin with, but my jaw muscles are particularly well-developed. I hate it so much, seriously.

I don't think this is simply a matter of fat, so I'm wondering if getting a procedure like Botox first would be the right choice, or if there are other options. People around me say that even just one injection of Botox can significantly soften the lines, but I'm not sure if the effect will be certain for someone like me whose muscles have been established since childhood. My biggest worry is that if I get it, my cheeks might just sink in, making my face look longer. I've heard that prolonged side effects of Botox are a common problem.

Are there any of you who, like me, have been worried about a square jaw since childhood and saw results from Botox treatments?