I Have A Lump On My Vaginal Area. And I

I have a lump on my vaginal area. And I think it's from shaving with a rusted razor I do have a light discharge clear about everyday and it don't have a odor the lump hasn't grown or anything and I been tested for a std already and it was negative my doctor said it was a cyst and and it hasn't gone away so I was curious to find out what may have happened.