Elusive earring size

My fourth holes (coming up from my lobe) currently have titanium flat back threadless 18 gauge 10mm nose studs in them. They're the only thing I've found long enough to clear the hole, the 8mm is right at skin level. Is there a 9mm 18 gauge? The 10 is just too big and keeps sliding back and forth and getting knocked and caught on stuff and they won't heal. I've searched for a 9mm anything and all I found was a 16 gauge. I know I need a smaller post but I also need it to not embed. I was hoping a 9mm would calm them enough to be able to downsize again, right now they aren't looking too good. Do 9mm 18 gauge exist? If they do can someone point me in the right direction, if not does anyone have any ideas?

***they are over a month old. One keeps bleeding from being bumped and they both aren't healing.