Although it is not possible to conclusively rule out oral cancer in the absence of any diagnostic data, the incidence of cancer in the anterior
hard palate is statistically quite low, and it is therefore unlikely that the lesion to which you refer represents a malignancy.
So, although this is almost certainly not cancer, it would be much more difficult to say what it is. It might be due to a physical trauma from hard or sharp food, or a thermal burn from that hot pizza. It might also be a secondary herpetic lesion similar to the cold sore you mentioned. It could also be due to a periodontal infection
in the adjacent incisor tooth, or a reactive lesion such as a pyogenic granuloma
, or a lesion of some mucocutaneous disorder, such as lichen planus
, or lupus. Or, it could be due to a yeast or deep mycotic infection, or a benign neoplasm such as a papilloma, or any of hundreds of other known clinical entities.
As you can see, speculation is not very useful when the broad list of possibilities cannot be narrowed down by any of the presenting characteristics of your lesion. Therefore, if the sore does not resolve within a two-week period of time, you should arrange for your dentist
to provide you with a formal diagnostic examination, which should be able to eliminate any ambiguity as to what this lesion may be.
Hope this helps...