First, you can do some exercise or massage to tighten your skin. In the process of losing weight, the skin is slack, mostly because of personal overeating, which leads to insufficient nutrition and serious loss of collagen. In this case, you can also eat more fresh fruits and vegetables, and add a little collagen appropriately to tighten the skin and enhance skin elasticity. You can also use some essential oils to tighten your skin. At the same time, it is suggested to increase physical exercise in order to become more compact. There is another way, you can also choose a plastic surgery hospital, do too many operations on loose skin, and then sew it up. This method is faster, but invasive treatment may also leave side effects such as scars, so it still supports the action of tightening the skin.