I Had a Chin Implant 6 Months Ago, I Still Cannot Fully Feel my Lower Lip, What Should I Do?

I had a chin implant 6 months ago, I still cannot fully feel my lower lip. Feeling did return to the skin on my chin, the outside of the lip about 80%, and I can feel the tissue I can lick. Though the meat from the middle of my chin to top of the lower lip is still numb, there is lack of control and feeling. At 3 months I was instructed to be patient because I had some feeling. I was just told if I wait longer I might permanently damage my nerve. How do I assess healing and what should I do?