Grey Area at NL After Juvederm Ultra Plus Yesterday?

It sounds most likely that what you are seeing the the Tyndall effect, a bluish discoloration seen when hyalauronic acid fillers are too close to the surface of the skin.  I would see the physician who injected your Juvederm to assess whether any intervention is necessary.

This can be caused by these fillers which like a colloid soultion and the Tyndall effect refract light and cause this bluish hue. If it does not dissipate in 2 weeks, see your injector/provider for possible hyaluronidase injection.