What Are My Medical Options If Methergine Fails To Clear The Remaining Tissue After A Medical Abortion?

i'm a 24y female. i took mifepristone and misoprostol for medical abortion. at that point my usg showed 1.35cm gestational tissue. i bled heavily for seven days and it gradually reduced. i had my rescan on day 10 and it showed 1cm hypoechoic area along posterior uterine wall with normal endometrial thickness. i have no fever or pain. my doctor prescribed me with methergine. if this fails what are my medical options. ?? i do not want to undergo surgery