Masseter hypertrophy is the enlargement of the masseter muscles, leading to a wider jawline and facial asymmetry. This condition can be genetic or caused by habits like teeth grinding and excessive chewing. Trismus, also known as lockjaw, is a condition where jaw movement becomes restricted, making it difficult to speak, chew, or open the mouth fully. Both conditions can be cosmetically bothersome and cause discomfort, but effective treatments can relax the jaw muscles and restore function.