Kybella is a fat dissolving treatment that has been FDA approved for use under the chin, or "double chin". The area is numbed topically, prior to multiple injections in which deoxycholic acid is injected to melt the fat. Kybella is a permanent treatment and should be used in conjunction with healthy diet and exercise. The most common side effect associated with kybella is swelling and can be significant for up to two weeks after treatment, but usually begins to improve about three days after treatment.