This is a huge question, so let's be really clear:
When you should NOT remove it: If you think you have an infection, leave the jewelry in! Removing it can cause the hole to close and trap bacteria inside, which can lead to an abscess. Not good.
When a piercer should swap it: If the jewelry is too tight, too loose, made of poor-quality metal, or clearly causing problems, a professional piercer can safely change it for you. They'll use proper sterilization and know how to do it without causing trauma. Make sure you ask your piercer not to use a piercing gun, which can make things worse!
Safe upgrade timing: Wait until your piercing is fully healed (3-6 months for nose piercings) before changing jewelry yourself. If you need to change it earlier due to material sensitivity or fit issues, have a professional do it.
How Long Does a Nose Piercing Infection Take to Heal?
Most nose piercing infections clear up within 3-7 days with proper care.
Mild infections should see improvement within 2-3 days of starting proper cleaning (or antibiotics if prescribed). Full healing can take 1-2 weeks.
Signs you're improving: Less redness, less swelling, less pain, less discharge. Things should get consistently better day by day.
What to do if it improves then flares again: This usually means you're irritating it somehow (snagging it, sleeping on it, using harsh products). Go back to gentle care and try to figure out what's causing the setback.