SC - you're doing all the right things, and I know it's very hard not to obsess. Especially with all that information (bad, good and inaccurate) available to us at the flick of a mouse.
To answer one of your questions: yes, SCC can certainly present with an unknown (also called occult) primary. Mine was such and in fact it's not all that unusual. In my case it had metastasized to what turned out to be 2 submandibular lymph nodes, although I could only feel one and it was about the size of a walnut. I had no lesions in my mouth or anywhere else.
I write this not to scare you but just give you some facts. Reread Cheryl's comment about it likely not being cancer. There are plenty of other causes of lesions, bumps and lumps and whatnot. Only the biopsy will tell you for sure.
I know it seems like forever to wait until Feb. 1st. Take a deep breath and then a few more. Your screen name says it all, and I'm holding you to it!
And ask any and all questions at any time. We're all with you in this!