I have had some molar tooth loss due to accident, six in total. Four on one side, two on the other. What can be done to increase jaw structure for the absence in terms of plastic surgery? Again, no fillers / injections due to hyper response to the like-anaphylaxis type reaction (convulsion, throat / tongue swelling. Can't do dental implants for same reason).
You should go to see the craniofacial plastic surgeons.
For improving the jaw line following molar loss from an accident, your first stop should be your dental profession. He can refer you to a prosthedontist (also a dental professional) who may be able to build an oral appliance to restore both form and function. Plastic surgery consultation can be considered after your dental health is optimized.