It is difficult to predict bruising, as it is very individualized. You can reduce the risk by discontinuing aspirin, ibuprofen, vitamin E, and fish oil for 2 weeks prior.The doctor may vary the technique and number of injections to reduce the risk, as well. The use of Prevedem topically and Arnica orally before may help. (Check with your doctor first). There are new products being evaluated now to reduce bruising after injections, so keep tuned....www.drmarylupo.com