White ulcer near vagina hole

I tried to couch with a tampon and apple cider vinegar with water it was painful on one side on my entrance and I took the tampon out I believe I broke the skin and it left me with s white sore it’s flat , hurts it I wipe to rough . Can anyone help 

*douche

Seek help to an ob-gyne near you...i prefer a lagy ob-gyne