I feel you. Sniffling makes me want to scream, punch, flip a table over and run away, which clearly isn’t acceptable in a classroom. Something that has helped me the slightest bit is either rubbing my foot across the carpet or rubbing one of my papers against another. They make a sound that is sort of similar to a sniffle so it kind of neutralizes it for me. Not the best coping strategy when the sounds happen every few seconds, but it’s all I can do. I also use white noise generators (aka hearing aids) that put white noise in my ear and I can adjust the volume, but I can’t use them often for my discussion-based classes because I can’t hear others talk/I can still hear some sniffling/they hurt my ears a little.
However, I have been able to get accommodations through my school (I’m in college too). I went to the counseling center and even though the psychologist didn’t know what misophonia was, she’s been trying to help me. She referred me to the head of disability services and I have a separate room for testing, free reign to step out of the room when I need to, and even flexible attendance. None of that has helped with the daily classroom setting we’re subjected to because I can’t really skip class anyway, but it’s better than nothing. Maybe if you talked to your professor and explained what was going on, she might be more accommodating and try to come up with something to help you (though trust me, I know there is very little that can be done). Or, you could go over her head to disability services. Good luck.