Shaping Nose After Juvederm Injection

Depending on how deep and where the Juvederm was placed it may be pretty well locked into place. It is really hard to answer your question without seeing your before photos and knowing exactly where the Juvederm was injected. For instance, in the lips it is possible to massage the material around a bit after the injection to flatten lumps and bumps. I doubt that you will be able to do this in the tip of a nose (though it can be done over the dorsum).
I would also worry that the deep pores of the supra tip area of the nose, which are full of bacteria, could cause a problem with excessive manipulation and might cause an infection if the Juvederm was injected too close to the skin. Once again, hard to answer this one without more info.
Hope this helps.

Yes, you can do some massage and shaping with pressure from your fingers.  The amount of change that can be made is usually minimal as the result really depends on the amount of material injected and where it is placed.  In short, attempting to shape it yourself will cause no problems.