I never had something as serious as you but a few years ago, I had a large tooth abscess (that developed because of a chipped tooth). I had to get it sucked away etc..., I'll spare all the gory details, needless to say it hurt like hell. I had to take lots of meds for the pain after (which was unbearable, trust me - if it wasn't for those painkillers I would have knifed my teeth out) and was essentially as responsive as a zombie for the following week - it was impossible to even think clearly, much less attempt to do any work. Although it wasn't any better before the operation, I couldn't open the mouth at all and every waking thought was directed to minimizing immediate pain.
And this one time a few months ago, I had a sinusitis which was causing dull toothache because the sinuses were pressing down on the gums, I was recommended Phenylephrine before sleep to ease the ache a bit... it knocked me unconscious and I woke up with a completely numb cheek and feeling extremely dizzy and could not concentrate clearly on anything (though I could still communicate and do simple arithmetic, I was unable to do anything more demanding). Yeah I know it's all teeth problems but I can deal with other types of pain fairly well, toothache just brings me to my knees everytime.
That's pretty similar to how my problems started. At first half my face was numb/tingling/burning along with my arm on the same side. Then the nerves on the left side started going nuts zapping me constantly, at times it feels like really painful gum nerve pain just above the roots of your teeth. That part of it is called Trigeminal Neuralgia, and it's caused by pressure on the trigeminal nerve. I finally got a prescription for neurontin for it, which made it somewhat manageable and has no negative side effects for me.
But then there was still a pain after toning down the TN, that felt like it was the worst case of deep sinusitis ever. An MRI showed a jelly bean "lesion" near the pituitary gland, smothering the trigeminal nerve and stuff around it. Eye problems started next.
That led to laying in a compromising position in the neurologists office as he stuck a BIG needle in my spine and waited 30 minutes while enough fluid dripped out.
Nothing showed up in the spinal fluid to explain the lesion, no cancer, bacteria, virus, etc. He gave an extremely rare diagnosis (Tolosa hunt syndrome) which also destroys your eye nerves/function, started me on steroids and said if it's not going away within a week or two then it's a tumor (cavernous sinus meningioma) requiring biopsy, but it's in a place they can't really get to, lot of important stuff there. It's been 5 days and no improvement so I'm just thinking through my next 3-6 months if I have to get laid out.
edit:: I actually got the referral to the neurologist from an orthodontist because I thought a tooth had moved up there, the main doctor I'd been seeing wasted months of my time telling me I had migraines and trying bullshit meds that just wasted a lot of time.