I got a very severe case swimmer's ear when I was 11 that lasted 3 weeks, I remember all I did was sit in a recliner and sob from the extreme pain I was in. I already had tinnitus and hyperacusis before that, but I've just always regretted not protecting my ears that one summer because of the "what if..." I've just learned that if you already have ear problems: don't tempt fait, protect yourself.
I like the "SureFire EP4 Sonic Defenders Plus filtered Earplugs" (that's their name on Amazon). They have a snap plug in them that I just love. Unsnap to hear everyone, snap back in to dive into the water and keep your ears safe. They're rated for 24 db, though earplugs that aren't foam or custom made never match up to their decibel ratings so just be warned if that's an issue for you. I seriously recommend these even if you have earplugs you like better, I wear these where I don't want to damage or lose my $200 ear plugs, namely in water like the pool and shower and where I could lose them in bed or camping.