I'm sorry, I just get an image of a kid saying "It might be a tumour" and Arnie saying "Its not a tumour!". Its been a routine joke around this house all year.

Of course its a question for an ENT. Not necessarily a different one, there is probably a reason he discounted it in the first place. If you go back and finds it still there he'll do a biopsy if it looks abnormal. A biopsy is the only definitive way to diagnose it.