Thanks for your question, and sorry to hear about your concerns. It is impossible for me to adequately diagnose your condition, and you should therefore speak with your doctor
about this condition. It is always appropriate to be concerned about cancer whenever you have a wound that does not heal as it should. Fortunately, however, there are many other explanations that could explain the symptoms that you are having. Many infectious condition such as viruses are quite common, and can cause painful oral ulcers on the insides of the lips or anywhere else inside the mouth. If you are using a product, such as tobacco, that decreases the body's natural ability to heal itself, the wound would therefore be quite likely to persist for some time. In fact, the product itself could be the cause of the painful lesion, although much more information would be needed before your doctor could claim that the product was the actual cause rather than just being associated. It is important to know that most doctors
now recommend strongly against tobacco products of all sorts due to a number of medical problems it can cause. Again, please speak with your doctor about your question.