What is the feeling and effect like with square jaw Botox?

They suggested that I get a square jaw Botox treatment to balance both sides.

However, since I tend to yawn frequently and use a lot of chewing force, I am most worried that the Botox might spread sideways after the square jaw injection, causing the corners of my mouth to look unnatural when I smile or my facial expression to become awkwardly fixed. I also think it would be difficult to cover up needle marks or minor bruises if they appear along the jawline. How long does the soreness or swelling typically last until the medication settles?

Has anyone here ever gotten square jaw Botox for facial asymmetry or to reduce masseter muscle size? Thank you for reading my question!!!