I've just had a bath, got water in my ear, and now I can't hear properly. Anything I can do?

Water in ears. Tilt head to drain excess water. You may also put a cotton ball at opening of canal to soak up excess water. Be careful not to go deep in the canal.
You could. lie with that ear down to allow it to run out. Putting a drop of rubbing alcohol in the ear canal with change the surface tension of the water and allow it to run out or evaporate faster.