I had hearing aids for the first time in December. The girl remarked that I had very small ear-holes but I didn't think it would cause a problem until I lost one. They cost me £3,000 and fortunately I had insured them.
But first I hunted everywhere I could think of, as did DD, sadly no sign. Just as I was about to give up and make my claim, I went out into the garden to check on my strawberry plants and there in the middle of the patch was my hearing aid! Fortunately the weather had been fine, so it was unharmed.
Another thought is have you sucked your ring up the hoover?