Suggest Treatment For Chronic Dry Cough And Metallic Taste In Mouth Post Coughing

I have had a dry cough for over a month now and metallic taste in my mouth after coughing. I also had a quarter sized bruise come up on the back of my knee overnight that concerns me because it is causing the entire back of my knee and some of my upper leg to ache, I have not done anything that would have cause my leg to bruise. Should I go see a specialist about this?