Precautions before treatment of intramuscular injection of hard knot infection: (1) localized hot compresses. When found that the intramuscular injection site has a hard knot, hot towels can be used to apply local hot compresses, but it must be noted that, if just after the injection soon can not be immediately hot compresses, must be 6 hours later, if the time is too short due to hot compresses can be caused by vascular congestion, local bleeding, so as not to enter the mouth of the needle to avoid infection of the water, if necessary, can also be added to the hot water with a little salt, the effect will be better. (2) medication wet compresses. With 50% magnesium sulfate solution, localized with gauze wet compresses, can achieve anti-inflammatory, analgesic, increase the function of absorption. (3) Available anti-inflammatory and analgesic cream can be applied locally to play the role of anti-inflammatory and analgesic, activating blood circulation and removing blood stasis. (4) Wound and dampness pain relief cream can be applied to the hard knot. (5) Apply cactus externally. (6) Yunnan Baiyao topical compress. (7) Some people believe that the use of potato cut into slices, applied to the local hard knot, can play a certain role in reducing swelling, the role of the knot, it may be worth a try.