Keep them if you have room to store it. My first blend was Old Ironsides. I liked the tin art and the name, but fell in love with the tobacco. For years I thought Latakia was the ONLY stuff worth smoking. Then I quit smoking a pipe for a few years in my mid 20's. When I picked it up again, Latakia just didn't agree with me at all. I'd try it every few years with the same result, but then suddenly probably 10+ years later I loved it again. If you come back to it later, you'll have lots of nicely aged stuff to come back to.
As for the reaction, I'd say this might change as well. For some reason, tons of McClelland blends used to do the same thing to me. It wasn't not like a tongue burn from smoking too fast, it's an almost immediate chemical reaction 3 puffs in. Even if the blend wasn't labeled McClellands, I could tell you right away it was theirs from my tongue blistering up. I find I can smoke those blends now without having the same reaction. Of course now that they're gone it does me little good ! But I saved all the blends I'd tried, even the ones that didn't agree with me, so I still have a bit squirreled away.