What are the side effects of Botox?

Hello. I am considering getting Botox, and while I am curious about the effectiveness, I am most worried about the side effects, so I am asking this question.

I have heard that Botox is a relatively simple procedure, but I have read that depending on the individual, various side effects can occur in addition to bruising, swelling, and pain. I am curious to know what the most common side effects are in reality.

In particular, I would like to know if getting Botox in the forehead or between the eyebrows can cause the eyelids to droop or the eyes to feel heavy, and if getting Botox for a square jaw can cause discomfort when chewing food or difficulty using the jaw muscles. I am also curious if, if these symptoms occur, they usually recover naturally over time.

I would also like to hear actual experiences from those who have experienced headaches, stiffness, asymmetry, or awkward facial expressions after the procedure, and how long these symptoms last.