Numbness of the mentalis nerve territory after a genioplasty is a possible complication. If you still have sensitivity, than it is more likely that the numbness (hypoaesthesia) will recover completely. Sometimes a long period of recovery is needed, about 6 months, 1 year, and sometimes after 2 years. The sensation that you will get after 2 years will be the definitive one. You can accelerate the healing process by taking B1,B6,B12 vitamin pills every 8 hours during 6 months, although the evidence of efficacy of this treatment is weak.
It is still too early to tell how much sensation will return. However, in most cases, a stretch injury will recover to a significant degree. If you are developing any sensations in that nerve this is typically a good sign that the nerve is repairing itself. Cutting of that nerve which would result in permanent numbness is very, very uncommon. I hope this information is helpful for you.
Stephen Weber MD, FACS
Denver Facial Plastic Surgeon
Your inferior alveolar nerve was probably injured with the old implant removal. Sensation may take several months to resolve and there is always the possibility of prolonged paresthesia. If you have tingling or itching or other unusual sensations in the lip or chin it is a good sign the nerve is recovering. Good luck. Donald R. Nunn MD, DDS Atlanta Plastic Surgeon.
Always best to see your operative surgeon first. There you can obtain an explanation of the issue../.
Based on your new information I still believe the nerve has been stretched and its function should return within 6 months.