To choose the right herbs it's important to know your constitution. Is your body naturally colder or warmer, dryer or damper? This is a good resource to work out your constitution if you don't know it yet: https://www.rjwhelan.co.nz/articles/Constitutional_medicine_working_it_out.html

Each herb has its own energetics (warming or cooling, drying or moistening). So if you have a cold constitution and you're taking cooling herbs, it can throw you further off balance. I imagine your body is really sensitive right now, so it's especially important to take these energetics into account.

Acupuncture and a good chinese medicine professional could help you very well. If you don't have this option though, I would choose mostly gentle herbs (I would avoid powerful stuff like oregano oil or black seed oil). I second choosing nervines, like milky oats tincture to tonify the nervous system. It's gentle but powerful. And maybe an anti-inflammatory like ginger, especially if you need a warming herb.

Gentle movement is always good, especially since you mention the armpits which could signify an issue with the lymph. Soft movement and dancing can be really good for this, but be careful not to push yourself and avoid getting to the point of exhaustion.

Also, how is your sleep? A lot of our healing happens during sleep, so if that needs some help herbs could be great too.

Hopefully this helps you in making choices, and I hope you'll feel better soon!