What Causes Recurring Lump In Vagina Post Hysterectomy?

I am 47 and had a total hysterectomy in July 2014. I have a reoccurring lump/cyst/varicose vein on my right private area near where my underwear sit, for going on a year now. I have had it treated twice from a vascular radiologist and injected to kill the vein. However it doesn't seem to be working. There was no blood flow when ultra sound applied. It went away for about a month but now it has returned. It gets filled up to a point where it is hard to walk, then it will release itself and seems to contain blood and a clear liquid but not puss. Can you help tell me what this could be please