What Are The Side Effects? Tenderness, swelling, firmness, bruising, pain, redness, discolouration, and itching are all temporary reactions that can occur following treatment. Some reactions can last for up to a week for skin injections and 2 weeks for lip injections. Reactions should subside within this timeframe. It is at the medical professionals discretion if they administer any medications to aid the healing process. The overall risk with dermal fillers is low and you will gladly see results straight away after treatment. Results are expected to last for several months to produce a beautiful, long-lasting results.