Could A Hot Water Bottle Have Caused Red, Swollen Welts With A White Film On My Vaginal Lip?

I’ve been sick for the past few days and I spelt with a hot water bottle inbetween my legs and I woke the next morning with a massive welt on the inside of my vaginal lip but there was also a smaller one further into the vagina but they’re both on the same side. It’s super red and swollen and there’s a white ish film on both bumps. I haven’t had sex before so I didn’t think it would be an STD and I just noticed it two days ago but i don’t know what to do what to heal it or what it is. The only thing I have done so far is polysporn.