Does nerve damage recover following pain after cheek filler - 5 months post injection? I am petrified.

This sounds like the infraorbital nerve was injured during injection. Don't know if the foramen was injected causing pressure on the nerve or the nerve was injured by the needle. In any case, I would treat this as a trigeminal neuralgia, and you are on one of the medications used for this. Sometimes the nerve does not recover and you must be prepared for this. Cannulas, in my opinion, are less likely to cause a problem like this, but this is a rare complication. If you can't live with the problem, there are more extreme measures such as surgery or injections to kill the nerve. I'd give it a year or 18 months before partaking in irreversible procedures.