Given that you've seen these doctors and they have given you a clean bill of health, I would do two things. Relax, and quit your association with tobacco. It will come to no good end. Remember that most oral cancers are time/dose related to tobacco. You are young, and compared to a patient who has been at it for a couple of decades, you are probably lucky enough to be giving it up before a serious condition changes your life. If you go to see an ENT regarding your blocked ear, he will probably be able to help you resolve things and put your mind at rest. Irritated papilla on the tongue which can feel like a burning sensation, are common in most people and usually come and go throughout your life. Dipping is not a viable, cancer free way of using tobacco...it will get you in the end if you continue. Trust me, I talk to people every week that thought otherwise and are fighting for their lives now.