Incompetent cervix

I'm 29w4 days and my cervix is soft. I had to have terbutaline to stop my contractions that were two minutes apart. My cervix is dilated 1cm but not all the way through because of scar tissue? The dr said it is swollen and red and was wondering if I've ever had surgery or a biopsy. I haven't had either so I don't know why my cervix is like that. Has anybody ever had anything like that?