Nerve damage from cheek and chin implant? I got silicone chin and cheek implants 15 months ago.

The surgeon used screws to anchor them. I keep waiting for the feeling to come back near my mouth. But there are two spots--one on my lower lip and one on my upper--that are still very numb. They tingle often, and sometimes my speech is encumbered by lack of lip dexterity because I'm numb. It's been over a year. Is this normal? Do I have nerve damage? Will it get better? Sometimes it seems to be getting worse! What should I do?