There is no evidence that repeat Juvederm injections cause lip cancer.
Rest assured that plumping your lips with Juvederm will not cause lip cancer (or any other cancer for that matter). Both Juvederm and Restylane the other hyaluronic acid filler are fantastic for lip volumizing. When it comes to lip treament, avoid fillers that can not be easily adjusted like the hyaluronic acid fillers. So avoid silicone oil, Radiesse, artefil, sculptra for the lip.