I was diagnosed at 24 - no tobacco and HPV negative. The day before I had my tumor biopsied, I felt like it started to feel better and almost cancelled my appointment. I would push to get a biopsy if you haven't already just for your peace of mind. From what I have researched, it seems that my leukoplakia did not start out malignant, but turned malignant after leaving it untreated for a year. I am sure you have nothing to worry about, but better safe than sorry!