MSFinals-6501

A patient who underwent abdominal surgery 12 hours ago now has a temperature of 38.2ºC. Their blood pressure is 118/78 mmHg, heart rate 68 beats per minute and respiratory rate 16 breaths/minute. The patient reports feeling pain around the incisional wound. On examination, the wound appears red and their chest is clear. What is the probable reason for the fever in this scenario?