I'm on orsythia. can i make my period shorter by starting a new pack after i've taken some of the blue pills of my old one? or finish blue pills?

Yes!: You can shorten the last week of pills if you like. For example, you can take the first 3 weeks of pills, and then only take the first 4 pills of the fourth week. On day 5 of the fourth week, you start the first pill of a new pack. This will shorten your periods and can improve PMS, headaches, etc. You must always take all of the first 3 weeks. As long as you do this, you will be protected.