What procedure is most effective and recommended for slimming and enhancing the lower face/jawline on a round, undefined face?

Hi, Usually the best way to decide on the procedure that helps you achieve jawline slimming & definition, is by evaluating your face in an in office appointment to go over your whole facial soft tissue, hard tissue & teeth. But generally speaking if you have Masseter muscles/ jaw muscles hypertrophy, you can get Botox (or other neuromodulators) for the Masseter muscles to relax the tension & bulkiness in the muscles, combined with biostimulating fillers in the jawlines to define your jawline & to give you more facial balance. This is a non invasive approach & if done properly, would give you natural looking results. Hope that helps! Best of luck. Dr. Dema Hilmi