Bleeding, infection, soreness and swelling are possible. The most significant risk is that your face may simply reabsorb all or most of the transferred fat. The chances of this happening can't be predicted for a given individual but is likely related of the mobility of the surrounding tissue. In my practice I minimize this risk by using Botox to temporarily relax the forehead muscles so that their movement doesn't interfere with the fat establishing a blood supply. Rare risks and complications include allergic reactions, discoloration, overcorrection, scarring, and embolism caused by a fat injected into a blood vessel (which can cause blindness). Proper technique and specialized injection cannulas that minimize the likelihood of entering a blood vessel are used to minimize this last risk. You can minimize all of these risks by finding an injector who has experience in fat transfer.Best wishes! Harry V. Wright MD