Not quite the same but DD I had 2 lots of the injection and it still wouldn't come away, thankfully a doctor got it out with forceps or theatre would have been the next step
DS last year no problem delivering placenta but I kept losing blood which wasn't slowing down, turned out I had clots round my cervix that had to be manually removed (sheer agony, worse than childbirth!) then a week later ended up back in hospital with endometritis scared myself stupid on Google etc thinking it would affect my fertility but here I am 13 weeks with #3 DS is a year old next month!
Speak to your doctor if you are really concerened thet would be best ones to ask