Silly question - nits or dandruff???

[WellyMummy]

An unpleasant parenting first for our family, DD1 had one live louse yesterday, only one and only her. I treated the whole family with Hedrin, yes I know it's only a treatment and not a preventative but I was working on the assumption that as a first timer I might not be as thoroughas to discover every bug!
The mere thought makes my skin creep. Have resolved to comb everyone several times per week to ensure we're properly clear.
I have read all I can about treatment, methods etc. But I can't find an answer to how to tell if the white bits on the comb are nits or dandruff? It's when I'm combing my own head so I can't look at the scalp!

Nit eggs are kinda shiny and round, have a bit of a transparency if you hold the comb up to light and are usually stuck at the base of strands of hair, not always easy to get out with a comb. But if you haven't found any nits on yourself then I doubt there will be any eggs.
But keep doing what you're doing, combing everyone's hair a couple times a day, because that is the only way you will get rid of them. In the bath, put condition in the hair so nothing can stick, then comb through. These treatment things don't seem to work.

Thank you!
Combing regaularly and gave bought a robo comb too.