When will forming a bone callus stop being a possible complication after the surgery?

Nasal bones don’t heal by callus formation so you should not expect callus to form. If your nose looks okay and you recently had surgery callus will not be a problem

Hi and welcome to our forum!
Callus represents "overgrowth" of new bone laid down during the healing process after rhinoplasty. The phenomenon is usually noted clinically within the first few months after the procedure. Remodeling of the bone then occurs over a period of up to several years.
Best wishes...