What can I do about painful lumps appearing 5 months after Juvederm?

Hello Scatterd.  Although rare, there are side effects that are consistent with what you describe.  Hard (not always painful) lumps that develop post dermal filler injections could be granulomas.  This type of hard cyst is the body's immune reaction walling off the product and surrounding with dense tissue.  These nodules can be addressed typically with steroid injections, but you should check in with your injector to have them evaluated.  Best of luck.

I recommend following up with your injector. If necessary, you can have it reversed with hyaluronidase and try a different technique next time. See an expert. Best, Dr. Emer

I encourage you to visit with your injector as your symptoms are not typical.  The product can be dissolved with hyaluronidase.  You may need medication to treat the swelling or potential infection.