My neck basically runs into my chin and I have very little jawline? (photo)

I have very little fat or sagging skin on my neck and I just had my lower jaw brought forward with orthognathic surgery (because I had an overbite). It still looks the same because my chin and neck join as one. The muscle (or whatever it is that runs up the throat to the chin) basically attaches a few centimetres from the end of my chin and makes it look like I have a sagging neck. Can anything be done to improve this?