Can you clearly see the difference before and after Botox?

I feel like my facial contours are sagging as I get older, so I am considering getting Botox.

My face looks big, especially because my salivary glands and jaw area are developed. I am curious if there are noticeable changes before and after the Botox procedure.

How long does it usually take to see visible results after the procedure? I've heard that while it varies by person and body type, the lines usually become smooth after about a month. I'm wondering if this is true.

Also, I heard that the pain is just a brief sting, but am I the only one who is scared just thinking about the needle going right into my face? ㅠㅠ I'm wondering if even someone as dramatic as me can get it without any trouble.