Can non-surgical nose fillers migrate over time?

You are asking an excellent question.  I have clients who present to me for non surgical rhinoplasty who have been injected in the past.  If they have been injected with a hyaluronic acid product such as Restylane or Restylane Lyft, then I use hyaluronidase to dissolve the filler in the nose prior to performing any further injections.  I have the client come back to my office a week later and we essentially start with a fresh slate.  Otherwise you will get filler which is at different stages of dissolving and that will lead to irregularities in the nose over time.

Widening of the nose after injectable fillers is more likely due to over correction, rather than migration. Thank you for your question. Sincerely, Dr. Joseph

Thank you for your question.  Though fillers can not replace rhinoplasty, they are a great alternative if you do not want surgery.  In my experience I haven't seen that fillers migrate.  I suggest scheduling a consultation with an experienced physician or injector for optimal results.  All the best!

What happens with repeat fillers is that they go by the path of least resistance. When we put fillers in the nose, or anywhere else, we are injecting a gel into an area of soft tissue. If there is a lump of filler or maybe some scarred tissue from old needle trauma or some bleeding in the past, the filler may end up going elsewhere. Once the filler is done and you leave the office, it does not migrate anywhere else

When filler injections are performed by a trained expert like a double board-certified facial plastic surgeon, the risks of complications are significantly diminished. Injectors with this degree of training understand the layers of the skin and how to properly place needles or cannulae for maximum effects without affecting blood vessels or causing lumpy areas to form. 
Fillers expand somewhat after injection, as Hyaluronic Acid gel absorbs water and will smooth out as it swells. This isn't exactly migration, as you mentioned, but it does explain minor changes especially during the first 2 weeks following injections.
I have never encountered a case of filler migration that would cause a deformity making a client look like an "avatar" character, but if this is a concern you have, you should make sure that your injector is properly trained in filler injections, and that they are an expert in nasal anatomy. 
I suggest having a double board-certified Facial Plastic and Reconstructive surgeon & E.N.T. for all nasal cosmetic procedures.

From experience, some patients presented to me with this "avatar" effect is usually injected with hyaluronic acid based fillers. While agreeing with all the plastic surgeons that non surgical nose enhancement or augmentation cannot replace rhinoplasty, it is advisable to discuss the desired outcome with your doctor to know which method is suitable for you. Every type of treatment hold its own risk which should be discussed before deciding whether or not to proceed with the procedure.
Generally, common non surgical nose enhancement are divided into 2 categories.
1. Nose Threads 
(this is done to lift the nose bridge or tips, threads are divided to many grades & prices varies too.)
2. Fillers
(this can be done to enhance nose bridge + tip height & shape , and to correct any sunken or uneven area eg: nose hump to a certain grade. Fillers also comes with variety of categories/grade & price varies)
in the pass few years I prefer using  Ellanse filler with canula injection method , it have provided my patients with very stable result. No Avatar effect have been reported since.

I would suggest that you seek consultations with some rhinoplasty experts. Many people like myself do not agree with fillers as an alternative when a  rhinoplasty is needed. They will make the nose bigger and can have some complications associated with injections to the nose. Best regards, Michael V. Elam, M.D.