I don't know how much it cost. It was many years ago my friend had it done and it was here in the US. The surgeon made a tiny incision in the inside of her mouth and inserted the silicone pad. It is a hard silicone, small and looked like a happy face smiley. It balanced out her face.
My friend didn't have any bruises but I would expect to have some bruising. She was out within the hour and I drove her to the store. We bought an ice pack. She didn't feel like talking much, but she was functioning. She didn't have nerve damage but I would expect that could be a possibility. Can you have a consulation with a surgeon?