I have small blisters or lumps around my vulva. More have been appearing over the last week or so and they are irrating.They are itchy sometimes but only seem to be really bad after sex and before and during my period. What could this be?"

Is there any kind of discharge that is not normal for you? Have you been tested for STI's recently? I suggest going to your doctor to be tested. It could be something as simple as a yeast infection, but given that you are sexually active, it could be something more serious.