My Grandson Popped His Knee Skiing L/6/17. He Did Not

My grandson popped his knee skiing l/6/17. He did not tell me about it until 1/10. He is 17 yrs. old. He has been putting an ice pack on it approx. every 4 hrs and taking ibuprophen. As of today the swelling does not appear to have gone down. Is there anything else we should be doing? Should I take him to the emergency room @ the hospital?