Sorry that you are still seeking answers for your symptoms, and that they are flaring up again! As others have said, there are some people that have the clinical signs and symptoms of CAPS that they have not been able to find the genetic cause at this time. Some have later found that they have a mutation for CAPS, or other conditions that is not expressed completely in their bodies, which is called somatic mosaicism. There are some special research facilities doing these tests, and many that were previously diagnosed as CAPS without the genetics now have found that they do have a mutation through these new tests. I can send you some information about this if you like. It is all very specialized research, but is really a big breakthrough in understanding these complex conditions.
In addition, there is another cause for some cases of Familial Cold Autoinflammatory Disease that is not caused by the NLRP3 gene for CAPS, but by NLRP12, which causes the same symptoms but has a different genetic origin. This is a very new discovery. Some people have been negative for the CAPS gene NLRP3 (CIAS1) but have been found to have this NLRP12 gene. Regardless of the genetic cause, they are suffering the same, and need help.
You also may have some other condition, but my point is to not give up hope, and find a doctor that will try to treat you and help you with your symptoms, regardless of what they find on a genetic test, as there is so much they still need to learn and discover about these conditions. The list of autoinflammatory diseases keeps growing too, as more discoveries are made. Newly classified conditions are coming up all the time.
There are some patients that have been given some of the medications used for autoinflammatory diseases to see if the drugs will help their symptoms, even if the genetics are negative. These things are between you and your doctor to discuss, and they are the best ones to determine what would be the best plan. This is very experimental, and is not the standard approach, nor the best for everyone, but it is worth discussing with your doctor. The challenge for these patients is insurance coverage for the drugs, when they don't have a clear cut diagnosis.
I am thinking of you, and appreciate that you are keeping us posted on things, and I really hope that you can get some relief soon for your symptoms.