I skip the "period pills" in the pack sometimes and just go to the next active week in the pack. It doesn't hurt and you are just as protected.
When you are on the pill, you DON'T ovulate or at least you SHOULDN'T. The hormones in the pill prevent ovulation, but if it happens for whatever reason, the hormones also mimic the hormones produced by a fertilized egg to prevent any sperm from trying to get in. Also, the reason why you have a period on the "period pills" is because those contain no hormone. The lack of hormone causes a sudden drop in hormone levels in the body and trigger a period. This also happens naturally in the body.
So skipping the "period pills" in the pack is fine, but I woudln't do it longer than 1 week. Also, if you skip that week for an extra active week, you should go on the period pills the week after so your body doesn't freak out.
I hope that was clear. Good luck