I have had something like this happen to me, but it was many years ago and has nothing to do with MG.

When my allergies started, before I learned how to recognize or treat the symptoms, I got lots of infections in my nose and throat and even had bronchitis a few times. I learned that when I started smelling odd smells, smells that seemed to be inside my nose, that it was time to get antibiotics because I had an infection. I have since learned to recognize my allergies long before they get so bad, but I still remember smelling those odd scents in my nose.

I hope this helps.