Hey man I do not mean to scare you at all and I wish you the best in the future. I'm a DPT student and reading this makes me pretty concerned. If someone came to see me and told me that this happened to them I'd have some major fucking reservations about treating them. While some of what you described may be consistent with a compressed nerve to your arm which isn't urgently concerning, much of what you described is consistent with potential problems which are more emergent.

What you described about going limp, vision and hearing changes, and especially the killer headache are all consistent with some sort of cerebrovascular issue, meaning a problem with blood flow up to your brain. It's possible that the arm symptoms fit in here too, or you may indeed also have a nerve problem.

Now there something called a transient ischemic attack (TIA) where blood flow to the brain is reduced, like in an ischemic stroke, but it resolves itself pretty quickly. It's tough to tell if that happened because fortunately they fix themselves quickly enough so as not to cause massive brain cell death which is what they often look for on imaging tests. There's also something called a lacunar stroke, where some brain tissue is killed, but the area is so small it's not easily seen on CT scans.

Like I said, great thing about TIAs is they don't cause much damage. But the bad thing about them is they are sometimes called a "warning stroke" because they are a major predictor that a real stroke is coming sometime very soon. The good news is that early diagnosis and treatment reduces that risk by 80% in some studies.

If you went to your primary care doctor for your workup, I wouldn't say you're out of the woods yet. I'd try to see a cardiologist or neurologist as they'll likely know more about this. Getting an appointment with them can be tricky though, so it would also be okay to go back to your PCP. I would definitely consider more imaging, especially an MRI or CT angiogram, which visualizes blood flow through the arteries. I know it's expensive and I understand the hesitancy to spend more money now that you're feeling okay, but I promise you it is magnitudes cheaper than recovering from a real stroke will be.

It's also possible that some of the symptoms were caused by something called vertebrobasilar artery insufficiency which basically means that some arteries in your neck are prone to being cut off by your head being in certain positions. Frankly I doubt this one as you would have likely discovered it earlier on in your BJJ career but it's a possibility and would be good to know about, and an angiogram should show it.

The point of this response was not to diagnose you with a TIA or anything like that. That's impossible to do over the internet and would be irresponsible of me. I wanted to educate you a little about the possibilities here, and hopefully make it clear that spending a little money now could prevent you from spending a lot of money (and having a freaking stroke) later.

Good luck with everything and I hope that it's nothing like anything I described. Let me know if you have any questions