I Have Had A Cold That Turned Into A Cough

I have had a cold that turned into a cough and has lasted at least 10 days, now I have small red spots on the back part of my tung and hard coughing, coughing up some small amounts of mucis . But question is my dermatologist has me on two 500mg of Keflex two times a day. One side affect is coughing, so should I go off the meds long enough to see if it goes away? Meds are for acne problems.