You're on the right path to keep her ears cleaned and free from infection and it's great that she will let you clean her ears like that
If her ear hair has been shaved for showing or for neatness to sell her, I would let that hair grow back to keep the bugs out --- that is most likely what those sores are from.
Once you have her ears wiped out with the povidine, if it's affordable and you can find a health food store that sells Patchouli oil (it's about $12/ounce in the health food stores) buy a bottle. It will last you a LONG LONG time.
Buy some mineral oil in WalMart.
When I mix it for fly spray, I put one cup mineral oil, 1/8th cup Patchouli oil in a fly spray bottle and fill it the rest of the way with water.
It always has to be shook up good before spraying. You could then spray some on a paper towel and rub her ears with it.
Don't soak her ears with it because it is oil and will draw dust like a magnet. Use just enough to lightly moisten the skin. The smell of the Patchouli oil should keep the bugs out.
It will keep the bugs out of her ears and also serve as a moisterizer.
If you can't get the Patchouli oil, buy the mineral oil and wipe it in her ears full strength after you clean them.
Diet is important too. I bought a horse three years ago that had warts in one ear. I took him off oat & corn based grain, started him on 2000 I.U. Capsules of people vit E per day and all that's left are the scars from those warts.
Not saying that would work for everyone, but Vit E is an immune booster and the body dumps what it doesn't need. There is no toxic build-up like there is with Vitamins A & D.
Hope this helps