What Causes Rash Like Rawness In Vagina?

i have a rash like rawness area on the outer lip of my vagina it seems to be healing and growing back new skin noticed it two days ago what could it b? im a female i weigh 93lbs 4ft 11in, could this b dry skin? in use body washes alot, and i have been taking alot of pain relievers for a toothpain recently plz help?