Hi iv got red spots size of small buttons on my soft palate in my mouth but before that happened a week ago i had a ulcer on the palatine is it cancer?

Need exam: Oral ulceration or known as apthous uclers is common and can be benign, though they are conditions that may have associated pathologies including chron's disease. Otherwise if your symptoms become a chronic, it is worth the time to have it examined.

Probably not: It is not possible to answer this question without a clinical exam. However, this may be a fungal infection, such as yeast (thrush) or a another condition altogether. I strongly recommend you see your primary care physician or an ENT fro an evaluation. If these lesions persist, there may be a need to take a small sample (biopsy) to confirm the diagnosis.