I keep earplugs with me as well (car, work, home, purse, and home on top of tickets, etc.). I had some ear pain over a year ago, from not wearing plugs at a show, and some guy yelled in my ear after the show. The doc said my ears were just sensitive to begin with and the yell exacerbated the problem. There are a zillion of nerves running from your ear, so I had some pain in my jaw and down my neck. Also had the ringing and loud noises made my ears ache - kids screaming & cell phones are the worst. I went to the doc, hearing fine. Just sensitive. They check your ears for fluid. They suggest Claritin (or similar product) to reduce the fluid in your ear. Stay away from alcohol, salt and caffeine. You can go get the fluid (two types of fluid and they can't see one) tested further if you are concerned. I suggest going to the doc just as a pre-caution. In fact, I'm going to schedule an appt. soon. The pain, ringing, cotton in the ear feeling does go away, but you need to rest them by avoiding loud sounds, reducing the fluid, or wear earplugs.
And yes, last night, it was (too) LOUD. Even the music between sets.
The plugs I got from the club weren't as good as mine, and I found some of my brand in the bottom of my purse. At CVS, earplugs are sold w/ a little plastic case you can stick about 4 into. I'm an old fart.