Rick and the others are right on target. I had a pretty good ulcer worn down in my ear canal before too long, but my audiologist made the serious mistake of putting my TransEar on the grinding machine (I didn't know better, so I had no problem with it at the time). It sure felt better, but I had to give it a week to heal (it was almost to the bone - as Rick said, there's not much room between the surface of the tissue and the bone up there). Laren at TransEar once told me that extremely fine sandpaper should be used, and to take off only about the thickness of a piece of skin at a time. I wanted to clarify just who thick a piece of skin she meant, and asked if she meant something as thin as what peels off about a week after a bad sun burn? She said that was it. After my audiologist got done with multiple trips to the grinder, my original TransEar almost flopped around in my ear.
Thanks to some great support from the folks at TransEar, I was able to get a remake back to the original mold, then they took a slight amount off right there at the company, and returned it. I never had to have it sanded, and the difference was noticeable, in terms of volume. Like others have said, a little sanding here and there in the first few weeks is entirely normal. After that, you'll hardly know it's there (but you'll sure learn to notice when you've forgotten to put it in!!).
Chris
