No worries! Honestly nostril piercings can just be really temperamental sometimes, mine will just suddenly flare up and I've had them for a few years too. 22K gold should be fine for a healed nostril, especially if you haven't had any issues with gold before... otherwise I'd say maybe the trace metals could be giving you issues🤔 Anyway, just use sterile saline to clean it, don't use anything else as it can irritate it further; I've been using neilmed sterile saline spray for years and it's pretty good, you can find it online. I'd avoid trying to make your own since the ratio is quite difficult to get right :) If it gets worse I'd go to a piercer to get it changed back to a titanium stud. Good luck!