First I would recommend stopping the tobacco use. It has many chemicals in it which are irritants to your mouth. When using tobacco, you are upping your odds of developing all kinds of problems, lung cancer, oral cancer, COPD, to name a few. Do yourself a huge favor and quit so you dont have to jeopardize our health. I know quitting is not easy, I am a former smoker. Whats much harder than quitting? Battling oral cancer!

If you have a sore in your mouth that has been there for over 2 weeks then you should see a professional to get it checked out. It does not sound like it is an open sore but more of a lump inside your cheeks/mouth. Unfortunately not all dentists are able to recognize oral cancer. Have they ever given you an oral cancer screening at your check up visits? If not, you should ask for one or switch to a dentist where they do the screenings. From what you have said, I doubt you have oral cancer. It does not usually appear in several places at once. Its not possible to guess what is going on in your mouth over the internet. I would suggest you make an appointment with an ENT or oral surgeon who is familiar with oral cancer. There are all kinds of things that it could be. Best thing to do is not put it off, get it checked out. They may need to do a biopsy to determine whats going on. Help yourself by getting rid of the tobacco so what ever is going on can heal.

Best wishes!