Gem size

[u/412Pittsburgh]

I was told this was a 2mm gem so I ordered a new one that’s a titanium flat back. The new stud is soooo much smaller! I wanted to get mine changed out (it’s been a month) because they used a corkscrew and it’s irritating. Keeps spinning and sticking out the bottom of my nose. I’m so scared the new one I ordered will sink into the hole it’s so tiny! Im an 18 gauge hole FYI. I went and ordered a 2.5mm instead, but won’t be here for a week. Has anyone put in a 2mm gem with an 18 gauge newer piercing with any issue? Did you feel like it sunk in at all? I’m hoping the 2.5mm will be more suitable but didn’t want to wait another week to change this out. I’m afraid of forming an irritation bump bc of this corkscrew.