I have a square jaw, so I think I need to get Botox, but I'm hesitating.

I have a square jaw, so I think I need to get Botox, but I'm not sure if it will be effective. It feels like the bone itself is protruding, rather than a problem with fat or muscle. Also, I've been told that the area under my mouth is short, which makes it look even more square. Would Botox be effective in a case like this? Please share any information you have.