|I know this answer is way late, but it might help someone else. I got a really bad systemic case a couple months ago, and it got on my tattoo. It made it look uber bad for a bit, but after a couple weeks the P.I. and the scarring went away (I always scar from it) it looked fine. So no, it wont damage the tattoo's permantly.
And as far as the ear canal, I would see a doctor. Whenever it's around the face, the safest thing is to see the doctor and the'll usually perscribe something that will get rid of it quicker than over the counter stuff.