After juvederm, I felt a lump in my neck later in the day. Could it be related to the juvederm treatment?

Where did you have the Juvederm injected? If you had the product injected in your face, it is highly unlikely the product migrated to your neck. If you did have product injected in your neck, it is likely It is product or swelling. Swelling is common with injections and can take 2 weeks to resolve. Hope this helps.

Please return to the injecting doctor for examination. Over the internet we can not even venture a guess.... 

There are a few scenarios that could explain your finding after Juvederm injection. The first is that the lump was there previously, and you noticed it after the injection. The second is that the lump is an inflammatory reaction to the injection, although it is unusual for this to happen do quickly. The third is a skin issue, such as a pimple or small cyst. It is unlikely for Juvederm to migrate from the lips to the neck. Please talk to your doctor. If this is an enlarged lymph node, it should be followed and evaluated if it doesn't resolve.I can't stress enough how important it is to have your injectable treatments performed by an expert injector. Board certified plastic surgeons are trained to appreciate your facial aesthetics and anatomy, understand how to choose the appropriate products for you, understand injection techniques and pitfalls, and are competent in treating complications. There are times when non- invasive treatments are effective, and times when surgery is the best answer. Your plastic surgeon is generally the individual best qualified to answer this question.