doesn't surprise me that your pain has diminished considerably from Pancreatitis, as the fast will reduce and eliminate the inflammation (itis), and the cause of pain, if continued for long enough.
Your question as to whether chewing-up some crackers, spitting them out and then rinsing your mouth will or could affect the benefits of your fast?
The answer would be that it will affect it but negligibly or minimally. Any food taken into the mouth and chewed will stimulate the beginnings of digestion (saliva) and also stimulate your digestive juices to a degree, but unless any nourishment is taken into the stomach then ketosis will continue as before.
What you are doing is tantalising your body into thinking that you are going to reintroduce food and break your fast, and could be described as a huge "let down" for it. If only the body could speak English, it would probably be swearing at you. (humor).