Hey chetan - not sure if you had your tongue rebuilt - I did, I have a semi hard ridge in the operative area that when my tongue finally is a normal size (it's still a little swollen from rads 3 months out) - will actually be the side of my tongue - I think the plastics guy shaped it that way. I have had one completely clear scan so I know it's not a tumor - in your case it could be the same - or perhaps a little scar tissue? Also on the right side (this gave me a mild freak out because this is my old tongue) I had a few hardened ridges like blisters but more hard than an actual blister. They were midway towards the back they were there from week three in rads and hung around until a week ago... They were in an area that was rubbing on my upper molars. I have a cross bite this means my mouth is small (despite the fact that most people who know me would disagree) and my teeth were crowded so two of my molars are in a little in a little from the natural tooth line - they were rubbing and irritating my tongue to no end... Making an irritated tongue even more so. Well last week I visited my dental oncologist and told him to file the two molars a little smoother. I told him why he said - your tongue is still swollen. Most people think their mouths are full of nothing - but it isn't it's full of tongue! When the swelling goes down you won't have the rubbing problem. I told him in my opinion the cancer I had may have been caused by long term irritation to the area - and I'm not looking for a repeat. He kind of poopooed that idea but filed them and now my tongue is almost completely healed from a blister stand point (still waiting for some of my poor taste buds to stand up and fall into line though) try not to worry too much but do have it checked out - just to ease your mind - the oral mucosa takes a while to heal after radiation. I still have a few blisters in the back corners of my mouth but they are painless - and my cheeks - particularly the left are still swollen - ( though they generally deflate somewhat during the day) - I do lymphatic massage so this helps both my neck and cheeks, and have it done professionally once a week -(it feels weird when I'm laying there because I can actually feel my tongue deflating somewhat) we think that we're finished radiation and we should heal but we've had some pretty nasty stuff done to us - so it takes a while. Take care!