Spanking injections usually choose the top of the gluteus maximus muscle to be injected, if hard lumps appear in the buttocks after injection, it may be caused by the fact that when injecting, the speed of pushing the drug is relatively fast, and the muscle has not been completely absorbed, and most of them don’t need to carry out special treatment at this time. As the drug is gradually absorbed, after a period of time they can recover, and usually there is no danger. Another possibility is that the depth of the injection is not deep enough to reach the muscle layer, causing an irritating reaction in the buttocks, most of which will be absorbed slowly over time. But there are also some patients are due to the local drug stimulation after the injection, resulting in an inflammatory reaction, after repeated injections many times, the inflammation is further aggravated, resulting in the final inflammation radicalization appeared a hard lump, this situation usually need to be surgically removed.