Hi there it does sound to me like you have an adhesion... a few people here have had them when they've had a small surgery that doesn't require a graft. It's almost like the healing area grows an anchor to hold it in place. I would definitely ask maybe for a ct scan to determine if everything is okay in that area. I was at my dentist years ago. and he noticed a white patch under my tongue. He sent me to an oral surgeon who removed it and biopsied it. The results were "Thickened skin" almost like a callous as a had a jagged molar there. I healed and that was that. 6 years later my tongue began to get sensitive in that area. It was red and sore. but no lesion just red and sore. The filling fell out on that molar, and I had it capped. Then it went from intermittent soreness to always sore. I went to the dr. after dealing with it for 18 mos. (thought it was because the cap was rubbing on it) had the cap filed numerous times - anyway I was referred to an ENT who looked at it and said... well it's just red, but we'll biopsy it. The day of the biopsy he said it was just red, again... but that he didn't know where to take the tissue from as there was nothing noteworthy to remove. He said if he tried to remove all the red area that was going to be huge *the entire left underside of my tongue* So he just snipped a random piece (if he'd felt around he would have noted a firm area near the back - I thought it was scar tissue from where my callous had been). I have no idea if he even pulled from that area - but to be honest whatever it was was under the skin and wasn't visible.
Results of biopsy... inflamed tissue...
he said go home and check to see if maybe I could have the molar filed, and be tested for food allergies.

I did all that. Jump ahead 2 more years. I had the molar beside the capped one also capped and the pain increased 100 fold. Went back to my dr. told him I still had this issue. He sent me to another ENT... this guy looked at the area in question - still red, still sore and said lichen planus. But he wanted to biopsy it.

Came back as a tumor... and NOT A SMALL ONE. it was 2.4 cm long by 1.4 cm deep and was just beginning to break through the skin. It was inside my tongue.

Moral... this cancer can be aggressive but can also take a while to get that way. I'd clearly had the tumor for at least 4 years... it was considered "well differentiated" but just after my biopsy, I had a lymphnode blow up, within two weeks, it didn't show up on an MRI or two CTs but I could feel it and when it was removed it was not only cancerous but had moved through the capsulated area into the skin around the node.

I would definitely have him take a good long look, and if you feel rushed or unimportant maybe get a second opinion... welcome and best of luck.