You've probably seen it happen: two friends get Botox the same week. One walks out looking rested and refreshed, like she finally caught up on sleep. The other swears nothing happened at all. Same product, wildly different outcomes — and it's one of the most common things people ask us about. Here's why results vary so much from person to person. **Muscle strength and facial anatomy** Every face is built differently. Some people have stronger, thicker facial muscles — often (