HI, I understand your query. Being diabetic it is to be noted that any type of infection, may take a severe form,not responding to treatment unless your blood sugar is controlled. The redness & pain you have strongly suggest inflammation.This might follow skin infection due to hair follicle infection-though you have not shaved in one week, even miner injury to the skin last time may take a fulminating form in a weeks period allergy to the cosmetics you use,underwear material, or fungal infection of vagina -all of these lead to severe itching & a fulminating inflammation in diabetic patients. * You should consult your Diabetologist , check your blood sugar level & get in controlled. - Blood work, microscopic testing of the vaginal swab to spot the causative agent followed by culture & sensitivity test will help in prescribing specific antibiotic , anti inflammatory drugs as per need.,which would solve your problem. Thanks.