In some cultures, it is less desirable to have a #squarejaw or a #definedjaw. Or sometimes the jaw is just too dominant of a feature on a face or too masculinizing. There are surgeries out there which break the #jaw bone in to reduce the width, but they are typically difficult to predict precisely, have a long recovery time, and have a notoriously high dissatisfaction rate due to asymmetries and other issues. If the muscles of the jaw are bulky, it is possibly to cause significant reduction in the width of the jaw just by atrophying them with #botox. #botoxinjections to the jaw take just a minute or so to perform and within about a month start narrowing the jaw. They typically keep working and continue to narrow the jaw for about 3 months. The injections usually need to be repeated once every 6-9 months.