Repeated muscle contractions from frowning, squinting or raising eyebrows cause skin to furrow and fold, gradually resulting in the formation of facial lines. Botox works beneath the surface and temporarily reduces the underlying muscle activity that causes moderate to severe from lines, crow's feet and forehead line in adults- to help them look visibly smoother. 

In general, Botox injections are meant to last about 4 months.

However the effects of your first treatment could wear off sooner. If that's the case. you'll need a follow-up treatment sooner after your first appointment. After that, you should be able to expect your treatments to begin lasting longer.