Non-surgical procedure to improve a square jaw
A square jaw is often due to large masseters (the muscles used for chewing). Botulinum neurotoxin can be injected into the masseters. This reduces the masseter bulk and slims down the lower face, giving it a more oval shape and a less angular jawline.
Sometimes enlarged parotid (salivary) glands can contribute to square jaw. This is often treated with neuromodulator injection to reduce the fullness of the jawline.
Dermal fillers are often added to give a more defined contour to the lower face