Because you missed BCP for 4 days this does increase your risk of pregnancy because the hormonal tablets contained in BCP gradually decrease when you miss a dose. This is why some women experience messed up periods when they miss a few pills.
If you've been on BCP for 3 months + I would say you should be protected this time but there is still a possibility of pregnancy. Personally I would wait till your period is late or doesn't arrive before you do a pregnancy test. Testing in 2 weeks may give you a inaccurate result.
You may experience break through bleeding or your period may be 4/5days late because of the missed pills.