Have four dental cleanings per year. Plus recent exam. Noticed white pimple of sorts on floor of mouth. Internet screams cancer. Should I be worried?

Internet Diagnosis. A lesion (if that is what it is) such as yours cannot be diagnosed over the internet. You visit your dentist four times per year and have what appears to be a healthy, solid relationship. It would be so much better to express your concerns to your dentist, someone who has seen you many times and can certainly alleviate your concerns.