There are many oral conditions that can cause your symptoms. Even though you guit smoking, which was the best thing you did, you risk is still there from changes in the eliphical cells, and takes time to go back to normal. Erythroplakia, a red smooth, velvity, surface level lesion, has a high propensity to transform to cancer, and is presenting in about 40% of them, but it can be something else. As mentioned, your best bet is to see an ENT. Good luck.
