Its difficult to provide individual advice without a photo, and (of course) a full examination is always better still. However..
Most of your swelling should have gone by now. The remaining firmness and contour changes around your scar will need some help to resolve. You should check with your plastic surgeon before starting any treatments that they have not requested. They will also be able to tell you if there is a seroma (fluid collection) still hanging around that will need drainage.
Assuming there is no seroma, then scar massage will help (you can do this yourself). If you can find a good massage therapist they should be able to help reduce any remaining fluid. I usually have my abdominoplasty patients massaged at their 4 week follow up appointment to help shift the remaining tissue fluid (oedema).
If this does not work, it is likely that some remaining fat will need to be removed, usually best done by liposuction.
Dr Gavin Sandercoe