Not all hypothyroid is autoimmune. Mine is not... just had the antibodies tested for again... normal. I am hypo and use 75mcg a day of levothyroxine. I've never tested positive on an autoimmune screen and I've had 2 of them. My right sided goiter receded after treatment. My left lobe is partially non-functional, with no explanation or reason known.
Of course tests are only a snapshot in time, and some autoimmune markers like ANA can change and fluctuate.
I do think it is a good idea to have testing first. It helps put you in the scheme of things. The new low cut off is 400 in US, and you should ideally be higher than that. I have a link to Dr. Snow's work, from 1999 in my B12 thread explaining that he found some people with relatively normal B12 levels around 400 or so who still improved with the supplement anyway. Which suggests that some people may have a greater need than others for some reason.
When you supplement you will want to use METHYLcobalamin because it is already bioactive. There is a DNA mutation that about 10% of people have called MTHFR polymorphism, and they cannot methylate B12 and folate. Cyano in most vitamins in most local stores is NOT active form, and hence may not work at all in these people. One doctor came to our board and commented not long ago that perhaps 30% are affected..as some studies he's seen now suggest. So using the active form is best. It has to be taken on an empty stomach because micrograms of drugs or anything can get lost in food/fiber in the GI tract. People who come here eventually may be low because their intrinsic factor is not working and hence passive absorption is all you have...so you have to have no food present to enable the small amount from the oral doses to get into your body. The same applies to your thyroid medication, by the way... empty stomach.
Vit D also can very low...get them both done. One cause of paresthesia around the mouth, etc is a sign of calcium impairment.
People with those Hashimoto's antibodies, may have gluten issues. When that happens, malabsorption occurs in the GI tract of many (not just D and B12) but many other nutrients.
Cara's website The Gluten File (she and I go WAY back a decade now), is very complete on the testing, you can have. Blood work, stool type, etc. She saved her family with this information and remains passionate to this day about it.
But first please give Bryanna the dental details she needs to make her evaluation of your nerve pain. She is very thorough and experienced and may have insights for you.
7 months is a long time for this to be going on IMO. The fact that is has moved over to the other side now, suggests a process of some sort. Since you had an MRI I assume showing your sinuses? ... that was clean?
What I think today, is use the doctors for the testing, and bring your numbers here. Their treatments are typically weak and ineffective. A shot of B12 once a month ? Pffffftttt... many people need more than that. And Using the RX D2? double Pffftttt... doesn't work. You will need D3 if low.
Healing you up you can do with guidance here. Testing you have to request from doctors. Naturopaths, load you up with many expensive things.... but here we start you differently and typically many people improve. Peripheral neuropathy is a huge subject --over 100 causes... and medicine ignores all but the ones that respond to IVIG. Our SubForum is growing with information daily:
If you are using statins for cholesterol? That will be something on that forum for you to consider. Statins prevent remyelination of damaged nerves and cause neuropathies among other things.
But do give Bryanna a chance to evaluate you. You can always PM her for privacy and me too if you want.