Pain 15 months post op face/neck lift - Is there imaging or a test to confirm the internal sutures dissolved fully?

I had a lower facelift/necklift 15 months ago & I still frequently have pain & I consistently have numbness where the internal stitches were located. Short of opening up the wounds is there any imaging technology that will confirm whether the stitches have dissolved? My surgeon said they should have resolved in no more than 12 months but my sensation has not changed & my neck is still flushed red where the platysma was sewn to the mastoid laterally. What are the potential L-T consequences?