If you don’t start bleeding after taking Cytotec / Misoprostol within 4 hours, you should still take the other 2 pills (don’t forget to follow all the instructions).
In some cases, bleeding after using Cytotec can take a little longer and may start in a period of 8 and 12 hours (there are reports of bleeding that started after 72 hours).
If you are still not bleeding, but you’re sure you are pregnant, then there is a chance it may be an ectopic pregnancy or that the abortion failed and you have an continuing pregnancy. You should get an ultrasound.
If you get to experience complications such as fever, fainting or severe abdominal pain, then you should seek medical help immediately, because you have probably suffered a rupture of the fallopian tube due to an ectopic pregnancy.