The causes of left apple muscle swelling are mainly related to infection, trauma, hyaluronic acid injection and other reasons. 1. Infection: when the left side of the face is infected, the left apple muscle will be swollen, which may be accompanied by redness, swelling, pain and other symptoms. Give active anti-infection treatment. 2. Trauma: when the left side of the apple muscle is traumatized, there will be a feeling of swelling, in the acute stage need to local cold compress. 3. Hyaluronic acid injection: If you have just finished injecting hyaluronic acid to fill in the apple muscle area, the swelling of the apple muscle of the face will gradually subside after a few days, and no special treatment is needed. There is no need to be anxious and nervous when the left side of the apple muscle is swollen, go to the outpatient clinic in the hospital, under the guidance of the doctor for the cause of the treatment.