Some side effects include swelling, redness, bruising, pain, and itching at the injection site. These side effects usually resolve within a few days. We try to minimize these by encouraging our clients to use arnica for a few days before treatment. In addition, we recommend pausing any vitamin or herbal supplements that are blood thinning. On the day of treatment, your clinician will use topical numbing cream and Pronox to make your procedure comfortable.