Hey quincali
I don't know what I could tell you about the tender nostrils situation but I imagine it might have something to do with the sensitivity of the nasal tissue. After all, the RAI, does just that: it burns things.
As for the taste in your mouth, no to worry, that's something that happens often and it's due to an inflamation of the parotid gland. The glad is situated at cheek level, infront of the ear and you might notice some swelling and tenderness in the area.
What happens is, as the glad gets irritated, it produces more saliva and the best way to avoid discomfort as much as possible is to "milk" the gland, massage the area pushing gently towards the mouth. A warm compress and eating something like lemon drops or, my personal favorite, just lemon slices in boiled water, after they've cooled down a bit, will work wonders.
To help with the pain anti-imflammatory ibuprofen or similars are an option and as i mentioned in a previous message, if you preffer more natural remedies, and if they actually work for you, I understand holy basil or tulsi are also a choice.
Best of luck and best of health.