What is wrong with my lower lip following lower Facelift surgery? It isn't working properly.

I had a lower facelift one year ago. My problem is that when I smile my bottom lip goes under my top teeth. This is especially troublesome when I try to talk while laughing and smiling. I put so much effort into trying to talk but it is noticeable that I'm trying to move my bottom lip so that I can articulate. I'm so frustrated. Were the muscles surrounding my bottom lip not positioned properly? Most importantly, can this be corrected? Thanks so much for reading.