. Botox usually takes up to a week for full effect. However, this does not mean, in your case, that the Botox will spread to any surrounding areas. Everyone is different and it sounds as if you have just had faster results than most. Good luck to you.
Botox takes 24 hours to 5 days, in general to achieve maximal result. Again, just because it acted quickly does not mean that it will spread and cause problems elsewhere.