My girlfriend has a lump below her vagina?

I was performing oral on my girlfriend when i noticed she has a lump on her vagina, i noticed and got scared and told her, she got scared and cried. I asked her to go to the doctors, presumably because she's embarrassed and scared. I totally forgot about it days later, again and we were about to do it again when i realised she had it, but i was even bigger, what should i do? and what could it be please help me i'm scared.