Will the Nose Look Longer if the Tip is De Projected?

Derotation (tip lowering) will increase the apparent length of the nose (see other comments on proper nomenclature). Projection will have nothing to do with it. Nostril retraction is a tricky thing to fix, if severe it usually requires a graft.

Hi Kako,    The answer is yes, it can.  I depends on how you do it.  Without a photo or the specifics of the surgical plan I couldn't say for sure but here are some things you can google for research.  When you want to lengthen a nose that is already operated on generally you will use caudal extension  grafts, infratip shield grafts, and rim grafts.  The rim graft is for the retracted nostril.  If the retracted nostril is particularly bad you may need a composite cartilage and skin graft to extend the length of the nostril. 

Tip projection is the distance the tip sticks out from the face. The answer to your question depends on what technique is used to decrease tip projection. If you decrease tip projection by decreasing the rotation you can give the the impression of a longer nose. Other techniques can also be used to lengthen the nose, such as adding grafts to the end of the septum. Neither of these approaches will fix a retracted nostril. I'm sorry if I have confused the issue, but ask your surgeon exactly what he will do.

 No, the nose appears longer or shorter as the tip is rotated more or less.  An over-rotated tip make the nose shorther etc.  Projection is how far off the face the nassal tip projects and has nothing to do with tip rotation.  Be very careful with these terms as they mean something completely different to Rhinoplasty Surgeons.