Jaw and neck muscles are rarely exercised in a gym setting. Over time, this can cause sagging skin, a less defined jawline, or even neck pain. These jawline exercises can help create a defined jawline and prevent neck pain, jaw pain, and headaches. eck crunches are like an abdominal crunch or curl. This activates neck muscles that are rarely used, so be sure to take it slow and stop if you feel any pain. 
Step 1: Lay down on your back and press your tongue to the roof of your mouth. 
Step 2: Bring your chin to your chest, lifting your head about two to three inches off the ground.Step 3: Slowly lower your head back down and repeat.
Vowel Exercises 
By sounding out vowels and stretching your mouth, this exercise targets the muscles around your lips. 
Step 1: Open your mouth to create an “O” sound. Exaggerate the vowel to tighten the muscles. Step 2: Then, open your mouth to create an exaggerated “E” sound. 
Step 3: Repeat the “O” and “E” movements.
Collarbone Backup
The collarbone exercise engages the muscles under your chin that support your jaw. Step 1: Sit down on the floor or in a chair. 
Step 2: Bring your head back several inches until you feel the muscles on the side of your neck contract, keeping your chest as still as possible and making sure that your ears stay over your shoulders. Keep your chin parallel with the floor as you move.
Step 3: Repeat the same motion, but this time pushing your head forward. The chin-up exercise lifts up the facial muscles in the lower half of your face, including your jaw. 
Step 1: Close your mouth and slowly push your jaw forward.
Step 2: Lift up your low lip and push up until you feel the muscles in your chin and jawline stretch. 
Step 3: Stay in this position for about 10 seconds before repeating the exercise.