Robbie,
It is impossible for us to diagnose this problem. As Cathy has said it is also in error to suggest that because there is pain it isn't cancer. Just as it is not correct to assume that because you have used tobacco you will get cancer.

The way these things resolve themselves is by a process of elimination. You are younger than the typical oral cancer patient. The fact that you have used tobacco however, means you have an increased risk of oral cancer. The odds that you have oral cancer are still fairly low. The professionals that you have seen are going to continue to let time resolve this, because they are pretty sure what it isn't. Yes you can continue to wait and see what happens. Take Cathy's advice and avoid all irritants. This list of irritants include coffee, soda (especially cola), alcohol and spicy food. Eat live culture yoghert and avoid sweets. If you do that and continue to brush gently several times a day for 2 weeks you should notice improvement. If not, go back to the professionals and get to the bottom of it.

Not to frighten you, it is important to know that cancer cannot be diagnosed by looks alone. It is a change at the cellular level. So the fact that this dosn't "feel" or "look" like cancer is not a conclusive diagnosis. Cancer or pre-cancer can be present with virtually invisable lesions.