Itchy small labia

The itch starts yesterday during the evening and has continue on till today. I've checked the area using the mirror but it's not swollen nor have any strange differences.

I can only think of three possible causes, the first two happened the day before the itch starts.

1) I've engaged in unprotected anal sex. He unknowingly entered the wrong hole before entering my vagina for a few seconds, until I told him that it's okay to do anal. After that, he washed his penis thoroughly with soap before we engaged in vaginal sex.

2) I was masturbating with a vibrator. For easy cleaning, I use a condom. I may be allergic to that certain condom because I recalled that we used that same type of condom before and I experienced slight itching after that which I just waited it out till it went away on its own.

3) I noticed a pimple on my small labia back in January. Initially it hurt a lot to even move about but it became itchy afterwards. I managed to "cure" it by popping the pimple gradually over a couple of days.

What do you think that is causing the itch right now, and is there any alternative way I can cure it without seeing a doctor? I haven't scratch it since it's a sensitive area, so I relied on just washing with water.