Can mentalis resuspension with mitek screws be repeated for further improvement?

This is never an easy problem to resolve and sometimes "better is the enemy of good enough" (Voltaire). I prefer Micro-Aire Endotines and and aggressive taping as opposed to Mitek screws. Sometimes a simultaneous vestibular reduction is helpful. The Mentalis strain would likely improve with botox.

Each time you have repeat surgery in the same area things get more complex and progress becomes more difficult.
Considering the number of procedures you’ve had there are probably inherent limitations due to scar tissue.
Most likely your last operation the surgeon try to get the best results possible.
Improving upon that may be possible. The best person to talk to is the person who did your last operation. They saw tissues first hand and it’s probably in the best position to give you an accurate answer.
Generally speaking multiple repeat operations simply make things more and more difficult with less chance of quality outcomes.
There are exceptions obviously but sometimes they are simply inherit limitations.
Putting yourself in the hands of a sufficiently skilled and experienced surgeon in the first place is very important.
Complex situation require accurate information and no one can give you a quality response without an examination and knowing your full history in detail.
If you want to pursue another operation then talk to your surgeon or have proper in person second opinion consultations.
Best,
Mats Hagstrom MD