Hot saline is possible to reduce the swelling, but it needs to be divided into cases, if the time of application is not right or some swelling, it will aggravate the symptoms. If it is a local subcutaneous hematoma caused by trauma, applying hot saline to the area two days after the local bleeding has stopped will promote the absorption of the subcutaneous hematoma and also promote the reflux of tissue exudate. Also, if lymphatic flow is slow, applying hot saline compresses to the area can also promote the swelling to subside. However, if the local swelling is caused by infection, it is not possible to use hot saline compresses, which will lead to the spread of infection and increase the swelling, which requires a visit to the hospital, the use of antibiotics and, if necessary, surgical treatment. There is also the swelling that occurs when you are just injured can not be used, this will aggravate the subcutaneous blood seepage, making the swelling more serious.