Expect swelling and bruising that start to fade within three days of treatment. Common side effects of Kybella include: • Injection site reactions. • Swelling • Bruising • Pain • Numbness • Redness • Itching • Warmth • Hardness • Tingling or burning sensation • Skin tightness Kybella swelling doesn’t last long. Swelling will typically peak about 20 to 28 hours after your procedure. It takes 48 hours for the selling to go away. Rarely that can take longer than 48. It usually depends on the dosage.