What Causes Swelling In Labia Minora After Oral Sex?

hey so everytime a guy fingers me my labia minora swells up and gets outside my vag. I just got tested for stds and the test came back negative, and my doc recently gave me medicine for a yeast infection but it still happens. When it does, i often get dizzy/light headed.

i have never used lubrication in the past and it seemed to be pretty dry last time. what should i do????

oh p.s. it didnt always used to be like this, but do you guys also know of any ways i can get more "wet" down there? if that is the problem.

THANKS!