Hi RAwalker, What DiveGirl is experiencing is all in the inner ear. If it’s a ruptured ear drum the last thing you want to do is introduce liquid of any kind to the ear canal as you run the risk of flushing debris into the inner ear. The Swimmers brew will work to dry out the outer ear canal between dives to keep bacteria from growing and causing an outer ear infection. She could have a rupture but she spoke of no pain in her ears and she has experienced this before but not for such a long time. I bet the rough boat ride along with the stress of a difficult dive added to the problem. All that stress keeps muscles tight so her Eustachian tubes may not drain as usual.
Keep us posted DiveGirl.