I expect to flair somewhat after a trauma, but that does not mean the NSD does not work for me, it just means I had a trauma.
With my spine and joints being more vulnerable to injury, of course this makes sense that if I am "traumatized" I am going to then be immobilized more and then when I go to move around, I am of course going to be even stiffer. Or, like today, having had a horse "traumatize" my bad knee joint early yesterday morning, my good knee and hips and various other body parts are now chiming along in unison because I did a tremendous amount of work yesterday anyway, and they had to compensate for the stiff and swollen knee.
This does not mean the diet doesn't work. It means a fat mare rolled into me after delivering her little bundle of joy. Thank Goodness for the diet, because otherwise I couldn't still be doing this sort of thing, delivering foals, at 3 am. Heck, I'm 48, how many 48 year old arthritic women do you know still able to do barn chores with a cane? If I had been on painkillers, I would have been too groggy. Of course, I am going to be goooood and stiff for several more days, and I cheated and took a single Aleve after the "trauma". But when you are not on daily drugs, that single dose has a whopping effect.
You probably had the disease all along, and it was smoldering, everybody gets little niggling aches and pains and it's hard to diagnose this disease early phase. The disease is a functional process of the body's metabolism which has a glitch. It's a digestive disease which manifests as joint/bone damage. I choose to try to change my metabolism by avoiding things that throw it out of kilter.
"Fairly serious car crash...." you may have picked up the triggering infection in the hospital, unknown, and the infection triggered the disease, but the trauma made you feel it more acutely.
Give the diet more time.