Cortisone injections generally are very safe methods for treating joint inflammation. Short-term side effects are uncommon, but can include lightening in the color of the skin at the injection site, bacterial infection, local bleeding from broken blood vessels, and aggravation of inflammation in the area injected. Long-term side effects depend on the dose and frequency of the injections. With higher doses and frequent injections, potential side effects can include thinning of the skin, bruising, weight gain, puffiness of the face, elevation of blood pressure, cataract formation, and thinning of bones. Patients with congestive heart failure, renal failure, or hypertension may have problems due to the effects of fluid retention several days after an injection.