Hi, My Boyfriend Was Playing A Competitive Game Of Sport

Hi, my boyfriend was playing a competitive game of sport yesterday morning when his lip got severely injured during a rough tackle. He was taken to the hospital as the left side of his upper lip was severely cut open and had 5 stitches. After the procedure was done, it all seemed fine however, after a night out with friends, his upper lip where the stitches were done began to swell dramatically. He decided it was nothing and rested but upon inspection this morning, it appears as though the left side of his upper lip has further increased in size and is filled with blood. Do you have any idea as to why his lip is reacting like this, what could have caused it and why? Also, is this normal?