Subcutaneous tissue injections may have complications such as localized hard nodules, localized infections, and pain at the injection site. 1. Localized nodules: mostly seen in patients who have been injected in the same area repeatedly for a long period of time. Once nodule occurs, doctors usually suggest using fresh potato slice paste, local hot compress, local red light irradiation method for treatment. 2. Local infection: mainly occurs when the injection is not strictly sterilized. By strengthening the aseptic operation, the occurrence of local infection can be avoided. 3. Pain: Some patients have strong pain at the injection site due to the type of drug injected or rough operation. In this case healthcare workers need to skillfully master the injection technique and do a good job of psychological comfort to reduce anxiety, which will help relieve the pain. In addition to the above, needle breakage, bleeding, and allergic reactions may also occur. If a complication of hypodermic injection occurs, healthcare personnel should be informed immediately and appropriate treatment measures should be taken.