How could I lower my arched nostrils? (photo)

Hello and thank you for your question. Based on your
photograph, you have alar retraction causing this appearance of your nostrils.  You may benefit from alar rim grafts to lower the position of your ala.  Make
sure you specifically look at before and after pictures of real patients
who have had this surgery performed by your surgeon and not just a computer
animation system.  You should be able to
view numerous pictures of actual patients with noses similar to yours performed
by your surgeon.  Best wishes and good luck.
Richard G. Reish, M.D. FACS
Harvard-trained plastic surgeon

Lowering an arched nostril is one of the more challenging endeavors in rhinoplasty.  The technique depends primarily on what the true problem is which can be multifactorial.  Sometimes it truly is arching of the nostril margin which can be caused by previous surgery, weak cartilage and scarring.  Other times it is less of an arched nostril and more of a hanging columella which is caused by excess cartilage in the septum and nasal spine.  
An in person exam will be more helpful with determining the true cause in you.  But there are several powerful methods for lowering a nostril margin.  Typically ear cartilage is too weak to hold the margin down, but septal cartilage and/or rib cartilage can usually hold the margin down longterm if used appropriately.  
Since this is a problem most frequently encountered in revision rhinoplasty, I would seek out a facial plastic surgeon who specializes in revision surgery and is comfortable with various grafting materials including rib grafts.  Good luck!