Does Botox last longer in zygomaticus muscle than other areas?

Thank you to doctors who took time to respond to me on here. I have had my eyes checked by primary doctor. My other botox issue: migration to zygomaticus major getting worse. The corner of my mouth is sort of folding over and drooping - is that because muscle has been out of use? Smile still uneven. Some reviews have said botox wears off quicker here big muscle others say it lasts longer. What should i expect? Now at 10 weeks.