3 weeks post op rhinoplasty, white stitch poking through outside of nose. Is this normal? (photo)

It is not normal for a stitch to poke out of the skin after rhinoplasty, but it is possible.  Your surgeon stated that the suture is dissolvable, but this could take several weeks to go away.  The simplest solution would be to see a surgeon near you and have it removed.  I would see a facial plastic surgeon or plastic surgeon in your area.  

This likely is a dissolvable suture that has come to the surface. I would contact your surgeon and this is easily removed in the office with minimal discomfort. 

It may be a suture from the inside as it looks like the surgery included an incision on the alar base. If you can't pull it out yourself, you can see a local plastic surgeon. 

I agree with the other DR answer on here.  Suture extrusion is not normal.  However it can happen.  It looks like a vicryl suture, and vicryl suture can "spit".  I would seek the advice of a FPS or PS near you.

Hi and welcome to our forum!
From your photograph, the culprit appears to be a multifilament deep absorbable suture which has worked its way to the surface. This is not unusual. However, the remnants that protrude thru the skin should be removed to prevent unnecessary scarring. The segment under the skin surface will dissolve if it cannot be removed.
It may be best to see a local plastic surgeon or your primary care physician for extraction.
Best wishes...

Dear Kayy92, I would seek an appointment with a surgeon near you that can address this current problem. You do not want to let the suture dissolve on its own as it may cause healing issues. Best regards, Michael V. Elam, M.D.