Weird blisters

I keep getting these random PAINFUL blisters pop up down there. The first time I had them it was SO BAD and they were everywhereee and I cried everytime I peed. Yellow discharge. I went to the doctor and of course the assumed herpes. I was blood tested for it however and it came back negative.... NOW I just found another one today but it’s just the one. So confused on what these are or how I’m getting them. Any ideas????

Yes I am sexually active but last time I had them I was tested for everything and it was negative.....