Implant Shifting After Rhinoplasty - Normal?

Each situation is unique and only your rhinoplasty surgeon knows the specific details of your procedure and should be the person commenting on post-operative questions such as this

The degree of mobility that you have in a nasal implant is very much related to the type of implant. If you have mobility in a Medpor style implant, there is a real chance that your implant is at risk for extrusion. Although there is little that you can do right now, do make your surgeon aware of this.

Implants can shift after rhinoplasty.  It takes time for the implant to become incorporated or surrounding tissue to have ingrowth into the implant.  Follow up with your surgeon as soon as possible.

It can happen. It's not the norm, but if you do enough nasal dorsal implants (of all kinds) you will see, and feel, a shift in some. Consult your plastic surgeon, and don't even begin to fret until six months have gone by. A few reasons to worry would be; redness, fever, purulence, of a general feeling of malaise with an accompanying large watery fullness in the dorsum. 

Unfortunately, im plants can shift at any time. You should see you surgeon to make sure that the implant is not being rejected. Retaping may be in order.