No, if you're going to do something about it, don't reduce the size of the chin implant. An sg would be a complete redo and may not conform well with your new jaw width if that's a wrap-around jaw implant. The most invasive option I would consider is getting a doctor that knows how to apply a boney paste to smooth out the crease. That involves cutting through the lower front gums though, which maybe you haven't had to deal with with the implants. It's a lot riskier to your lower lip size, movement, and nerves compared to cutting through the submental region.