Open your mouth as wide as possible, make an O-shape, and then close it. Do it 200 times a day. If you have more free time, it doesn't hurt to exercise more 100 times, and the effect will come faster. It is normal to feel a little sore during the period, because there is too little facial muscle exercise at ordinary times, so it is uncomfortable to do such intense sports suddenly. You can take a break and continue to do it until you finish 200 exercises. If you find it difficult to exercise your face in a task-based way every day, you can also do facial massage (massage the fleshiest part of your face with your fingers counterclockwise) and make faces when you have time. Of course, the effect is not as good as 200.

Another way is to look up slightly, put your thumb under your chin, then scrape up along your face, and then scrape back along your face, counting once. Do this ten times a day for several months, and the effect will be remarkable.