May have gotten benyzol peroxide near vagina, had butt acne on lower butt close to vagina. vagina now itchy and burns, could this be the cause?

Yes: The genital tissues can be intolerant of the drying effect of this preparation. Don't use that product anywhere below the nipple line.

Yes: Many people are allergic to benzoyl peroxide, and also all gels and some creams are somewhat irritating to mucous membrane (such as vagina, mouth, nose). So you could have a chemical sensitivity and/or allergy. Take cool (sitz) baths and apply cool compresses, take some tylenol (acetaminophen) and see if it gets better. If not, see someone. Needless to say, don't use this product near to vagina again!