When will an FDA approved filler for the nose possibly be available in the US? What is Silicon 1000 worst possible side effect?

I don't recommend Silicon 1000 for the nose. I recommend getting a formal evaluation with a cosmetic dermatologist to go over your desired results. Facial fillers (voluma, restylane, juvederm) can be used to improve the symmetry of the nose. However, surgery would be needed to improve nostrils or overall shape. You'll want to see someone meticulous. See an expert. Best, Dr. Emer

You are correct that temporary gel fillers like Juvederm and Restylane, may lead to vascular occlusion, dead skin, and blindness in a small minority of procedures. Injectable microdroplet silicone has been used safely for well over 50 years for permanent, nonsurgical rhinoplastic treatments. The worst side effects include overcorrection, and visible product - nodules and bumps, and these rarely occur in the nose. Hope this helps! Dr Joseph

Minor defects of the bridge (dorsum), central nose and tip of the nose can be very precisely and quickly corrected with fillers.  Improved definition of the tip, and straightening of the dorsum may be achieved. This may also result in straighter, thinner appearing nose. Reduction of a prominent dorsum or tip requires surgery.
Various temporary fillers are available Radiesse, Voluma and Lyft are options. Fillers which may last many years include Bellafill and fat injections.  Depending on your expectations for longevity and budget (pricing between $500 and $1900) a product can be chosen to best fit your needs.
There are no fillers that have been tested in this area by the FDA and therefor are considered "off label use".  Careful conservative correction should be performed. Silicon although initially resulting in good results may cause lumping or allergic reactions in the future which are very difficult if not impossible to correct.
Please consult in person with an experienced Board Certified Plastic Surgeon prior to making treatment decisions.