it is possible that the act of intercourse or the condom caused irritation of the labia minora. i am not sure if you had just had intercourse the second time you had the burning sensation. if you did then that may very well be the reason. it is also possible that there is a sexually transmitted infection despite your negative testing. it depends on what you were tested for and what you were not tested for. there are so many stds that is would be very difficult to test for everything. the most common testing is for gonorrhea and chlamydia. in addition i usually recommend testing for herpes as well as hiv. the burning sensation may also be from a non-sexually transmitted infection such as yeast or bacteria. regardless you should schedule an exam and discuss this with your doctor.
what can cause buring of the labia minora. i've been sleeping with my boyfriend of 6months and we always use protection. after the last time we did i noticed that afterward my labia minora had bit of a burning sensation. i also had the sensation when i urinated afterward. a few days went by and i was fine and then again today i had the sensation. i know it's not an std because we were both just checked and came back cleared. i'm just curious as to what could cause it all of a sudden it's not painful just a little uncomfortable.