Jawline slimming or masseters reduction for cosmetic purposes is a simple effective procedure that involves the injection of the neurotoxin botulinum type A into the large masseter muscles to create a slim and more feminine jawline. Botulinum toxin can soften the appearance of the jawline, leading to dramatic changes in face shape after regular treatment. A slimmer jawline also results in more prominent cheekbones and chin, which are especially important for women, who typically want high cheekbones and a clean jawline.