After the injection there is a lump on top of the skin, there may be the following aspects of the reason. 1, may be the local drug deposition in the subcutaneous tissue, which led to the. 2, may be a local hot compress or local rubbing. This situation can generally be given local hot compresses or local rubbing, after the drug dissipation and absorption, immediately able to disappear. 2, there may be a local needle mouth place there are symptoms of skin allergies. Commonly used in the injection of drug allergy, or used to disinfect the antiseptic solution, such as povidone-iodine or alcohol allergy, resulting in local arching up like a rash. Generally, the symptoms are mainly itchy. 3, may be the puncture of the needle mouth, there is a puncture caused by subcutaneous capillary rupture, bleeding, which led to the formation of a small hematoma.