Other side effects include 1) the face becoming too slim, 2) the jowls appearing more prominent because the back of the face is less bulky.There is not typically any swelling with the botox injection, unless a bruise forms. Masseter Botox is a non-surgical cosmetic treatment that involves injecting Botulinum Toxin Type A (Botox, Dysport, Xeomin, Juveau ) into the masseter muscles located at the angle of the jaw. Patients typically experience mild swelling, bruising, redness, and pain at the injection site. These side effects resolve on their own within a week or two after the procedure. Severe Botox side effects are rare. They include: Difficulty in swallowing and breathing The Side Effects of Masseter Botox Masseter Botox Cost Masseter Botox Summary Masseter Botox Overview Masseter Botox is used in the masseter muscle to change the shape of the face, make the wrinkles less noticeable and manage the pain. Botox is the trade name of onabotulinumtoxinA. Which is an injectable muscle relaxer. By relaxing the masseter muscles, masseters Botox can significantly reduce symptoms like jaw pain, headaches, and teeth damage linked to these conditions (Guarda-Nardini, Manfredini & Salamone, 2008) [^3^]. What are the risks and side effects of masseter Botox? Knowing the anatomy of the face and injecting in the designated 'safe' areas of the masseter is incredibly important, says Dr. Ronagh. It can help to prevent the spread of the Botox into a small muscle known as the rigorous, which can result in an asymmetric smile. 3TvJp.