NO he could NOT have told you it was caused by allergies. How would he know? He could give you a list of ALL the things that MIGHT have caused it perhaps, but what good would that have done you? A differential diagnosis starts with a list of all possibilities, and one by one eliminates them until the culprit is left. Sometimes like in MS, it is only the elimination of all other possibilites that you end up with a diagnosis. You have a long journey to sort out the many things you have going on.

You can ask all the questions you want here, but understand you are describing things that are not customary to the symptoms that the majority of us have had related to oral cancers, so we can't help you with most of them. You clearly have many medical issues, but they are not typical of oral cancers, and so what people have to offer here, (except to encourage you to continue to seek out doctors that will continue to explore your symptoms looking for answers) isn't much.