I've had this a few times over the last few years. Had no idea it had to do with diabetes. I was only diagnosed type 2 in September this year but have had high bg readings on and off for 30+ years. I remember seeing my dentist about it where I used to live at least 13 years ago. He couldn't find any reason for it but suggested a vitamin deficiency. Think it was b vitamins. It did go but does come back every so often. It's like having eaten pepper and still having the corns in my mouth. Strange.