Suggest Treatment For Congestion, Dry Throat And Cough

Hello, as the weather started warming up a few weeks ago, I became sick.. much like many others started to. In the morning, I would be very congested. At night, my throat would become dry, and I would start to cough. Over the course of 2 weeks, the coughing is pretty much gone, as well as the congestion. However, the other day I felt as if there was something caught in my throat... near the larynx. I tried coughing to dislodge this irritant. No luck. Then I viewed the back of my throat through a mirror and proper lighting. I noticed that very far back, almost out of sight, there appeared to be a darker patch (darker than surrounding tissue) with several (3-4) white spots within. I am also an ex-smoker, 28yrs old.