I Have Been Suffering From Silent Reflux For The Past

I have been suffering from silent reflux for the past week which is not causing heart burn but is producing lots of mucus and has resulted in a severe cough, laryngitis and nasal congestion. my GP is treating it with Lansoprazole and says it may take a couple of weeks to settle. In the last 48 hours I have developed severe pain in my sinuses and yellow discharge from my nose. This is not viral as I haven't got a cold. I am away from home so can't get back to my gp for a few days but I have access to cephalexin that I carry with me for UTIs. I am wandering if I should start taking it as I think I may have developed a bacterial sinus infection.