How Safe Is Undergoing Abortion Through Pill?

I went to get an abortion today and the dr told me my. Cervix was closed and that he couldn t dialate me so know I have to come back in for the pill Is that going to be just as effective I recieved a Pap smear and all was ok but now I m a bit nervous should there be anything to worry about? Is this common? Because I m very scared and lost and i really wanted the abortion is there a possibility that I can t have one