Chewing will help improve your jawline more. However, if you do it poorly, you'll build a cheek muscles and look floated. I recommend you chew chewing gum for 2 to 3 hours daily, the harder the gum, the better. Make sure you chew with your mouth closed. If your jaw begins to feel sore after a few days of chewing, take a break. You must have your jaw joint checked before starting any harder for long. Chewing.