How many sessions of square jaw Botox are usually recommended?

I want to reduce the overdeveloped jaw muscles under my ears to create a smooth jawline. I heard that after just one injection, the muscles gradually shrink and the face becomes slimmer. I am wondering if I can achieve a complete change with just a single session, or if I need to get injections periodically to solidify the slim look.

Generally, how many sessions of square jaw Botox are recommended during dermatology consultations? I have heard that receiving injections consistently at intervals of 4 to 6 months for at least three times helps maintain the reduced muscle size for a long time, and I would like to know if this is true. I am also curious if the line refinement effect is clearly visible once the recommended number of sessions is completed. I would appreciate advice from those who have experience receiving square jaw Botox regularly.