My almost 92 year old Mother has severe burning pain in her mouth when she eats. Coffee makes it better. Last 20 min. Coughing/sneezing. Started close to 10 years ago with spicy food. Has gotten worse over time. Dentists cannot figure it out. She is now in rehab due to a fall and says everything makes her mouth burn. She is now refusing all food and drink. This morning I brought her watermelon. She had one little bite, said her mouth was burning, and then she starting coughing, sneezing, and getting watery eyes. Granted, she's never been good at discomfort and tends to exaggerate, but her reaction is pretty impressive. At this point, I'm trying to find a solution, as opposed to a cause. She is refusing benedryl/milanta mix on her gums. I'm thinking maybe a saliva substitute, Sensidine toothpaste, or anything else that might help. Thoughts? (Her own teeth, lots of caps, no dentures.) Thanks.