I had juverderm lip fillers done nearly 2 years ago, however I still have prominent lumps in my bottom lip. Is this normal?

It is uncommon for Juvederm to last longer than a year in the lips; although it is possible. Return to your injector for a follow up. if the lump is concluded as product you can discuss going ahead with a hyaluronidase injection to dissolve the product. 

It would be very unusual for Juvederm to still be present two years after injection into the lips.  Most fillers do not last as long here as they do in other areas of the face, and are usually gone in about 6-9 months.  Are you sure it was only Juvederm and not a more permanent filler?  If it is a lump of Juvederm, an injection of hylauronidase will eliminate it. 

I recommend seeing your doctor to determine if this lump is from the Juvederm or a granuloma at which point treatment can be determined. It is rare that Juvederm lasts more than a year but it does occur in some instances.