<s>[INST] pI started out with what I thought was a canker soar but after putting powdered elm on it realized their was another inside the bottom of my teeth (the floor of my inside teeth...my gums are red and see a few white patches on them Would this be oral cancer? I have been using preroxide to kill what is in there?? [/INST] No this would not be an oral cancer but yes it can be a pre-cancerous lesion though. If you have any habit of tobacco chewing or smoking I would suggest you to discontinue that if not and still you have such a patch it could be due to fungal infection in which case you will be able to scrape that patch, and it would appear more like curd. Also, please get rid of using peroxide as it would only exaggerate the problem if used without knowing the cause. For further investigations I would suggest you to get a biopsy and clarify what it is and only then take whatever medication is needed. </s>