Hi lilliepop
Sorry to hear you're still suffering. Have you tried the dentist for advice. That was the first place I went to when the problem started, must have been at least 15 years ago. He did prescribe something, I can't remember if it was a cream or a pill to suck. It didn't work anyway. When I went back the only other advice I got was a vitamin deficiency, I think b vitamin. It did go but as I've said before it does come back every now and then.
My sugar levels have been up and down for the last 30 years. Regular blood tests over the years and finally diagnosed in September type 2. Have no idea if it's related to diabetes though. Are you on medications for any other illnesses it could be side effect. It could even be from anxiety, as it can affect us in so many different ways. I know I was having problems when mine first started but didn't put the 2 together.
I would see the dentist if you haven't already. They can refer you for further tests or just give you some advice to help.
My advice though is not to ask Dr Google. That's guaranteed to make you anxious as he will have you suffering from every illness possible.
Try to relax and see your dentist.
Let me know how you get on.