Swelling, itching, and irritation of vaginal lips

Hi I am 13 and have had my period for a year. My vagina started itching the other day so I just put neosporin on it and it stopped itching for awhile and I thought I was okay, but it kept on happening. I was just going to put some more on and I realized that my vaginal lips were swelling and were very red. I haven't had any discharge so I don't think it is a yeast infection of some sort. Please help