I've had a dry cough for the last three months, and while I'm generally feeling fine with no fever or anything like that, the cough just won't completely go away. I tried taking Zed S syrup, Corex T syrup, and Bro Clear for three days, but it doesn't seem to clear up entirely. I still get a bit of a cough when I gargle. Could you recommend a medicine that might really help clear it up?