I took plan b four days after unprotected sex will it still work?

It might: Plan B is a progesterone agent which usually works by preventing ovulation so no egg is available to be fertilized by the sperm, or by preventing implantation of a fertilized egg. It is most effective when taken within 72 hours (3 days) of unprotected intercourse, but there is evidence that it can work up to 5 days after (but less likely). Sex is always safest within a committed marriage