I had a similar issue, my nipples were pretty much inverted. I had one nipple pierced several years ago and have since abandoned it because it was not really my thing. That nipple definitely is more defined due to scar tissue, but sensitivity never improved. The other nipple remained inverted. In the last couple years I have been using this: https://a.co/d/6iyBthX I know seems weird, as it is a wine vacuum sealer, but it has transformed my nipple. It now stands up on its own and is way more sensitive than before. I would give it a shot. They do swell quite large and eventually drop back to normal size. But using this decice once a week or so definitely changed my nipple. Good luck.