I Am 31 Years Old,recently I Underwent A Medical Abortion

I am 31 years old,recently I underwent a medical abortion .. Doctor game me two tablets then two days after she gave me four tablets,as, soon as I took them i started bleeding,I passed blood clots every time I went to loo.on 2nd day,normal bleeding was there. After ten days doctor scanned me,some clots were visible in my womb,so doctor gave me two more pills,again passed some clots.after 10 days iwas scanned again . Report says there are still 16 mm tissues inside.does that means I have to go through d&c.what if I do not go for d&c.does there any risk