Suggest Treatment For Severe Knee Pain

I am taking 20 mg tablets of prednisone, 2 at a time once daily for knee pain. The pain is severe. I have taken the tablets for 3 d.ays. Today I also took 2 advil and 4 hours later 2 motrin before I remembered that the doctor said not to use these, but to take Tylenol. What should I do now? And, what interaction adverse could occur?