Sprains with bruises can not judge whether it is good or bad, also can not judge the severity of the injury. Localized bruising after back sprains can only indicate that the small blood vessels under the skin are currently ruptured causing subcutaneous bleeding, after which a bruise will be formed at the epidermis. This situation can not be analyzed whether it is good or bad, and can not judge the severity of the injury, because it can not be ruled out that the bruise may be followed by edema, redness, pain and other symptoms. To determine the severity of bruising after a sprain, you can analyze it by doing X-ray, MRI and other auxiliary tests, which will help you to know whether there is any damage to important tissues after the sprain and whether there is any fracture and so on. If you only find localized bruising, it is recommended to apply appropriate ice packs within 72 hours, and then switch to heat packs after 72 hours; those who suffer from pain should seek medical attention in a timely manner and receive targeted treatment under the guidance of a medical professional.