There have been no permanent side effects reported for Jaw Line Reshaping with Muscle Relaxing Injections procedures. Most patients will have regular treatments for many years without ever encountering an issue. After treatment, minor swelling may occur but this is easily covered with make-up if required. Small marks, like mosquito bites, may also appear following treatment but this will only last for a few minutes. If the injection is put in too high it can affect your smile for 2 to 3 months.