Hi Judy
i didnt really want another biopsy after the first (very painful biopsy) came back negative. I even said "thanks but no thanks" to the ENT who did the first one, then 2 months later said we needed another.

A routine trip to the dentist 3 months after that, resulted in a late Friday afternoon rush to his oral surgeon friend to schedule in the second biopsy which came back positive.

Doesnt mean yours will come back positive, but answers your questions about whether you can have a negative one first and then a positive.

all the best for your own results.