How can I help inflammation-based nerve damage be temporary?

You're drinking a lot of water, which makes me worry about Overhydration (I agree that you probably get net-benefit from the extra water, but excess water still causes problems in standard ways). This is because the blood needs a perfect ratio of water to other resources, such as electrolytes, and drinking water and then peeing it out consumes those resources (note that your body is probably consuming and peeing out water in order to perform some other task related to your disease, which can also consume resources). I recommend drinking a lot of water during meals, having a few sips of milk or pedialyte or a bite of cheese with every glass of water that you have between meals. It's important to note that pedialyte and cheese might have excessive salt which you also need to get rid of during recovery; look at the nutrition facts of all food, avoid eating out, definitely avoid ordering food, and make sure the food you cook has more salt since that will make it much easier to resist the temptation to order food and also avoid buying salty foods.

take 325mg of aspirin 3x/day on the theory that (i) it's unlikely to hurt and (ii) it could plausibly help because it's anti-inflammatory.

Since you're also already drinking a lot of water, I recommend having a lot of that intake be tea instead of water. Decaf green tea, ginger tea worked great for me to reduce inflammation. I know that most of the inflammation already happened, but preventing further inflammation from random causes will help with the healing. This is why you absolutely must stop eating sugar ASAP as it is an inflammation nightmare. Sugar is addictive and has a very unpleasant withdrawal with physical symptoms, but right now is the critical phase of recovery. Obviously, alcohol is also out of the question.

For further inflammation reduction, you can rotate between ibuprofen and naproxen in addition to aspiring if you're willing to have a no-pill puffer time in between each switch in order to reduce the risk of interactions, but make sure to not take naproxen for more than 1.5 days in a row as doing that can cause more harm than good. If you still use alcohol (do not) then do everything you can to avoid alcohol interactions with anything but ibuprofen. This is not medical advice, and it will only reduce inflammation. You should talk to your doctor about reducing inflammation, as the most powerful inflammation reducers are prescription only. These are all ordinary inflammation-reducing aspirin-like pills, the advice in this paragraph is nothing special.

I'm not sure how helpful it is, but this is everything useful I know that I couldn't just find by using google scholar. Also, if you're sedentary due to nerve pain or for any reason, just doing 5 minutes of jumping jacks per day or going on a lesiurely walk for 30 minutes can work wonders (even if it hurts). Also, if your current doctor doesn't feel like helping you mitigate brain damage, then that's definitely grounds to go get second opinions. Email doctors ahead of time so they can do research before meeting you, if you ask them for the first time in person and they don't know without research, the might feel pressured to think up stuff on the spot in order to maintain their appearance/status as an expert. Mainly, bite the bullet ASAP and stop eating sugar or foods that quietly sneak sugar into the nutrition facts, since sugar causes massive inflammation that will aggravate any recovery, and preventing sugar from reintroducing inflammation during the healing process is the biggest net-benefit I can think of. It's probably worth it to go as far as avoiding fruit, for the time being.

My answer is very long, but none of it contains very satisfying advice, so if someone has other advice it probably isn't already mentioned here.

What specific factors led you to conclude that you had shingles?