What is this?

So on the 12th of December I sucked this guys dick. 2 days later I had a canker sore on my lip. And soon after that ever since that day I have been getting more and more. I don’t know if it was related to that or what I’m eating. I am still getting them. The first one I have it just started to clear up but it took a whole month. It still hurts a little. I know for a fact he was not with any other girls. I just don’t know if i am getting sores in my mouth is related to that or something else.