What is a Granuloma and What Causes It?

Granulomas are a specific inflammatory reaction that is seen in soft tissue as a response to foreign bodies. The popularity of Juvederm and Restylane came about as a result of their high safety profiles and hence, their low rates of granuloma formation. Granulomas can occur, nonetheless, from any foreign body and require either surgical excision or TAC injection.

Tara,
Granulomas can occur after injections. However, just because you have a "lump" it does not mean it is a granuloma. Lumps after injections can be caused by localized palpable product, hematomas, swelling and granulomas.
The first three occur early since they are due to the product or the procedure. The granulomas occur later - days to weeks - since they are due to an inflammatory reaction around the the product or nidus of infection.
Clinic exam may help differentiate what is causing the problem. I hope this is helpful.