Is It Normal for the Lower Lip to Feel Numb Weeks After Chin Implant?

Numbness present weeks after a chin implant is due to the mental nerve being stretched or swollen. The good news is that the feeling typically comes back to normal over time.

The problems that you describe can be temporary, especially if it has been only 4 weeks. Unfortunately they can be a longer term problem. I would certainly speak with your surgeon because removal or repositioning of the implant may be necessary to resolve your problems.