You might try some of that fungus ointment. Cut back on the dust baths as well. Sometimes too many or too long of a dust bath will cause the ears to dry out. You can use some really intensive hand cream as well. The fungus ointment is greasy and will make the fur mat down around the base of the ear but it's basically easy to put any type of ointment on - just put it on your fingers and then rub it in both sides of the ear. Some chins have odd bumps on their ears too and I've been told that they are fungus carriers and yet others say they aren't. Have you ever had a fungus outbreak? I would imagine if you haven't then this is probably just dry skin.
Ronda