Has my septoplasty procedure failed? I'm 3 1/2 weeks post op and have been experiencing drainage, crustiness, and blockage.

Assuming you have had surgery performed  by a Board certified Facial Plastic Surgeon or an Otolaryngologist with vast experience in Septoplasty - you have nothing to worry about !  It is quite routine for many patients following septoplasty surgery to have nasal drainage, crustiness, an asymmetrical airway (mostly due to swelling, crusting and drainage) and slight discomfort with nose blowing - some patients will experience some or all  all of these issues for 3 to 6 months (and some will have these concerns  for up to a year or more) following surgery.  Many surgeons may suggest to you to start irrigating your nose with a saline solution starting 10 to 20 days following surgery, which may help resolve many of these symptoms faster, so be sure to check with your talented surgeon to see if this may help you out.  Good luck to you and your new airway !!