Injection site reactions may occur as a result of RHA filler injections and may include swelling, redness, itching, bruising, or infection. Swelling and bruising may be minimized with firm pressure and the application of ice packs before and/or after treatment. Infection is rare and easily treatable with antibiotics. Allergic reactions may also occur. Very rarely, the obstruction or compression of a blood vessel may lead to skin necrosis, but the risk can be minimized with proper technique.