What is the ruling on mewing, which is used for health and beauty purposes?

The "mewing" exercises are described as natural practices aimed at improving the shape of the lower jaw, combating wrinkles, straightening teeth, and alleviating jaw pain. They rely on two exercises: first, pressing the tongue against the palate behind the front teeth, and second, moving a straw with the lips. There is no scientific proof of their effectiveness yet. There is no religious impediment to practicing these exercises if their benefit is proven, as they fall under permissible treatment.