Does Botox sit in cell or is it metabolized quickly with motor function being regained ~ 3 months?

I'm wondering if botox is sitting in cell for ~3 months or if it goes in, does its cleaving, and is metabolized with a few days. Then during the ~3 months movement is regained during sprouting process. I'm not very comfortable with idea of chemical sitting there for 3 months but more comfortable with it going in, doing it's work, being metabolized quickly, and the natural process of regaining function occurring over ~3 months.