Skipping period on BC

[merenator.livejournal.com]

I use ortho tri cyclen and I skipped my last period. There's a bit of spotting now, but nothing big. I was reading that with ortho tri cyclen, you need to start the second pack backwards, which I didn't know last time. First, is this true? And second, does it change the efficacy of the pill? Thank you:)