You need to tell your mom cuz you can’t go to a doctor you are still a virgin and lots of teens masturbate. If she’s surprised just show her Walt Disney subliminal messages on YouTube. Sex is literally everywhere in music and everywhere. That’s why people are obsessed with it.
This sounds very much like a yeast infection, which women get from time to time - it is not necessarily related to any sexual activity. Don't be afraid to tell your mom, because this is just a normal, but terribly unpleasant, event for females, and it can easily be cured.
Don't tell her what you think caused it, and because you aren't a doctor you might be wrong anyway. You probably need to get looked at by a doctor whenever an infection like this occurs.