Hello, I have gone through your query and understood the concern. In the current scenario, the rash seems to have developed as an allergic reaction to the lubricant you have used. Infection, on the other hand, is not so sudden and is associated with increased vaginal discharge which is often with a specific odor, general symptoms like fever and enlarged lymph nodes. Often the sexual partner is also affected. There can also be an associated urinary tract infection and menstrual disturbances. Diagnosis can be made through clinical evaluation, swab and blood tests. In future, do not use such lubricants. You can go for the K-Y jelly instead. Do not douche or use strong soap solutions over the genital region. You can use ice pack and zinc oxide creams. Inform your health care provider if there is no relief. Hope this helps.