I am not active but both of your comments really help thank you.
Are you sexually active? I am 32 and 22 wks prego, i had one that was a normal pimple and felt the same as you. But it was not red, to the Dr.
It wouldn't be "on top", but otherwise sounds like a Bartholin's cyst. Look it up on Google Images to confirm. If it is, you could try soaking in a hot tub to get it to drain. If it gets too bad you'll have to see a doctor. Neosporin won't help. Good luck.