Probably one of the Slayer shows I've seen. I remember after one of them, I had to get my ears syringed twice. I am not sure if it's because of Slayer or not, because it was within a few weeks the syringing was done.
Strangely, the second time after seeing them, I had them syringed again, but I actually had some type of ear blockage about a week before the show. They couldn't be syringed at the time, but after I got it softened up, they syringed it. The syringing the second time around definitely had nothing to do with the concert.