Has anyone had salivary gland Botox? What are the effects like? Is it different from square jaw Botox?

The skin under my ears and below my chin looked particularly bulging, so I thought I had gained weight. But after doing some research, I found out that it could actually be due to enlarged salivary glands! I heard that getting salivary gland Botox reduces their size and makes the jawline look much slimmer. Has anyone tried this? I've had square jaw Botox before, but I'm curious about the sensation during the injection and if there are any side effects. I'm hesitating because I'm a bit of a scaredy-cat, as I saw reviews mentioning a dull ache when swallowing. Please leave a comment!