why is it oral cancer when other explanations are more plausible? it could be a canker sore, inflammed gums from gingivitis, or as others said the beginnings of an infection
in my life, I've not ever had a lymph node swell to the point that I could see it. Last year I had ear infectin, sinus infection, throat infection and bronchitis all at the same time--yes I was a lovely picture to be sure... still no swollen nodes in my neck or jawline. NOT every infection will cause a node to swell even if you tend to do that.
if you are that concerned about it, give your dentist a call. I'm betting he/she could fit you in the schedule the same day or in just a day. My dentist has a couple of emergency appointments available in the schedule everyday. I've even used them a time or two.