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 is unusual but Juvederm can last for two years.  Part of it may be absorbed and parts may still be present and look like lumps.  The easiest way to know what is causing the lumps is to inject the antidote (hyaluronidase) in the lumps and itshould dissolve quickly if there is Juvederm in it.    Then you can have fresh Juvederm injected in a few days.

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.