Painless "sore" inside labia majora

[Molly8799]

I have a medium sized painless bump on my labia, way up where the labia ends. It has been around for about a week now with no change. It isn't  perfeclty round, which makes it seem more blistery like but it doesnt seem fluid filled. It kind of reminds me of a burn, but i haven't burnt myself there (that i know of). It is red and the skin is raised. The skin around it also seems slightly irritated. It isn't painful, just a little bit itchy from time to time.

Through my research, it doesn't seem herpes like (especially since it hasn't popped and isn't painful or clustered).

After being with someone i lost trust in, i got tested for STDs around a year ago.At that time i also had a sore on my labia (different location) and the doctor said it didn't look like herpes, but im not sure if she tested for it along with everyhting else.  I have also had a LOT of blood work done lately.

Would herpes virus come up during blood work if they are testing for a lot of different things?