Canker sore or Wisdom tooth?

What does a wisdom tooth coming in feel like? I have been told in the past by my orthodontist that I don’t have any wisdom teeth (like I just didn’t have them at all) but my dentist (who I don’t really trust bc I got a tooth infection in one tooth due to sinuses and he said I had to get that tooth and the tooth on the opposite side of my mouth removed) told me I had two bottom wisdom teeth. I think I have a canker sore over where my wisdom tooth is supposed to be but how can you tell if it’s a tooth or a canker sore?