Why do I have hard visible lumps after filler in forehead lines?

There is swelling after any fillers and Juvederm pulls water to itself right after injection. Your bumps could be from either of these, or it could be too much product in the area. Keep your hands away from the area and don't press on the bumps. If things don't look like you expected about 10-14 days from your initial injection, then see your injector for a follow-up. "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."