Question about some medicine & I’m almost 20w

So I was prescribed that metronidazole vagina gel

For Bv. And I am suppose to tske it 2 times a day for 5 days.

I’m not sure exactly what bv is but all I know is this medicine (I’ve only took it 3 days) and it’s making me itch down there really bad.. and I tried to have sex with my boyfriend last night and it hurt way too bad but that could be because we didn’t have sex for a couple days, idk I’m not sure. I don’t know anything about the medicine just that my doctor told me too so I did, and I have to take it for two more days and I really dont want if it is going to make this itching worse cuz I can’t stand it

And I don’t know what to do to help the itching either .. please any advice would be VERY helpful.