As per Dr. Quynh-Giao Sartor, MD, FAAD, a board certified dermatologist in Houston, TX, paralysis is temporary, expression lines slowly return 3 to 6 months after treatment. The clinical effects of Botox disappear within 3 to 6 months. That means you’ll need regular sessions to stay wrinkle-free. Otherwise, Sartor says, your creases will eventually return to baseline.
However, Patricia Wexler, M.D., of Wexler Dermatology in Manhattan Botox says that facial muscles naturally weaken over time and going overboard in a certain area could have unwanted consequences. "If you do too much Botox on your forehead for many, many years, the muscles will get weaker and flatter," cautions Wexler, adding that the skin can also appear thinner and looser. Moreover, as your muscles become weaker, they can start to recruit surrounding muscles when you make facial expressions. "If one stops using their forehead muscles, they may start squinting using their nose and have wrinkles along the side of their nose," she explains. Translation: You need even more Botox for the newly recruited muscles, says Wexler.
Hence, getting Botox is a personal choice. It is not definitively proved that it will prevent wrinkles in the old age.
Sources:
https://greatist.com/health/does-botox-prevent-wrinkles
https://www.vogue.com/article/preventative-botox-injections-twenty-somethings-expert-guide-wrinkles-fine-lines-eyes-lips-forehead