Will marginal mandibular nerve damage heal after a facelift?

The different degrees of damage of the nerve vary from the milder called neuropraxia to the highest which is called neurotmesis. It depends on the type of surgery you had. If your nerve is just bruised, usually the affect will return after a few weeks or months, If it's completely cut and not repaired then it will not alleviate. Four and a half months is a long time, and you should address this with your surgeon as soon as possible.

Dear Mandy6026,Thank you for your question. After a facelift, facial nerve weakness can be seen and is either temporary or permanent. After 6-12 months if you have not seen any improvement, it is unlikely you will recover that function and the deficit may be permanent.Good luck,Nirmal R. Nathan, M.D.Certified, American Board of Plastic SurgeryMember, American Society of Plastic Surgeons

and anticipate the worst... but if you have some movement of the muscle group, recovery will usually follow.  And you should see some progress as time passes and healing continues. Wishing you the best...

Yes, there is a good chance that this can recover, especially if there is some hint of movement.  Nerve regeneration can continue to improve for 1 - 2 years after injury.  The mechanism of injury will determine the recovery, but most are 'neuropraxia's' where the nerve has been stretched, and recovery is progressive.

I too am sorry to hear this happened.  Movement can come back as late as 18 months after an injury.  A stretch injury could easily result in paralysis but typically will recover completely.  If the nerve was actually cut even then it can recover but recovery may not be complete.