The lesions on my tongue started as painless leukoplakia when I was 19 or 20. Over the years, they would "flare up" with ulcers and sores that were biopsied and a couple of times my tongue was resected. They came back as mild dysplasia, chronic inflammation, leukoplakia, and a few other things over the years. It was always on the same region of my tongue. I was diagnosed with SCC in April this year and I'm 33. So it was about 13 years from the very first noticeable change in my mouth until my cancer diagnosis. My doc said these things do not always progress into cancer and that there isn't really a good way to predict which ones will. It sounds like you are doing the right things and your doctors are staying on top of the situation. It never hurts to get a second opinion if it will make you feel more comfortable.