Thanks for the IEM suggestions, guys. I'll be looking into those soon.
I just left these burning most of the day yesterday and overnight. I have to say, from a complete noob who knows nothing about hi-fi and doesn't consider himself an audiophile, I can definitely notice the harshness settling down. I can listen to the same song I was having problems with, at a much higher volume, and it already sounds way smoother and actually fairly pleasant now (when it would nearly pierce my ears at a lower volume before). I'll leave these burning for the rest of the weekend and give my impressions then.