Allergan Botox (onabotulinumtoxinA) is an FDA-approved, prescription-only injectable treatment used to temporarily smooth moderate to severe facial wrinkles—specifically crow's feet, frown lines, and forehead lines—and treat various medical conditions like chronic migraines and excessive sweating. Developed by Allergan Aesthetics, it works by relaxing targeted muscles, with results usually lasting up to 4 months.