What could cause fluctuating swelling 8 years post rhinoplasty?

Unfortunately this is something that can be seen after rhinoplasty especially in people with thick skin.  Now assuming that you don't have an implant like goretex or silicone or something else in your nose, then it may be simply be related to the face that you've undergone a rhinoplasty.  While not common, after surgery sometimes you can see daily or weekly fluctuations in swelling.  Most of the time patients will complain that exercise, excess heat, alcohol (especially wine) and excess salt intake will all make the swelling worse.  Try and keep a log of what makes your nose swell worse and try and minimize salt intake less than 200mg per meal and see if that helps.  
Sometimes repeat steroid injections will help keep the swelling at bay.  Almost always this problem will resolve itself but it can be unpredictable at times.  
I know it's a frustrating problem but hopefully this helps shed some light on it for you.  

Hello. Great question. However, images and an internal examination are needed to provide an accurate assessment to your concerns. Please visit a board certified plastic surgeon for a detailed surgical plan to achieve your desired results.