Does a saddle nose form gradually?

Hi Sam and thank you for your question regarding a saddle nose deformity -- in almost all situations this is a chronic problem.  It develops gradually, not over a few days or weeks.  Typically this is due to a trauma to your septum, prior nasal surgery, or chronic cocaine use.Hope this helps.Mark K Markarian, MD, MSPHHarvard-trained Aesthetic Plastic Surgeon

In my experience saddle noses develop slowly over time, and usually are related to having snorted a lot of cocaine, injury to the septum, or as a result of prior surgery that affected the nose.  Be sure to discuss your goals and concerns with your board certified plastic surgeon and consider the pros and the cons. Be certain your surgeon is properly certified.  I've attached a link where you can start your search. 

A saddle nose occurs when the septum cannot support the weight of the nose and there is collapse with a visible saddling of the nose. It is rare from a piercing of the septum for this to happen. It may be possible from a large perforation of the septum from cocaine, trauma, a medical condition, or an infection. Saddles can occur quickly with acute trauma or infection, or slowly from a slow erosive process. See a facial plastic surgeon in person for an evaluation if you are concerned.

if you had a piercing and it was uneventful and there was no infection you should not worry about nasal collapse. Thousands of people have pieces of their septum removed completely in order to straighten it and they do not have nasal  collapse

Nasal collapse occurs gradually over time and is most commonly seen in patients who have had repeated nasal trauma - like hockey players - or in people who use cocaine in their nose which causes chronic destruction of the mucous lining and cartilage of the septum.
you should  be fine