Sadi, I have gotten those before. I asked my obgyn about it, and she said it is very normal and, aside from being painful, they are not dangerous in any way. Whenever I got one, it was usually right after my period.
My best advice is to try and keep the area as dry as possible. That's the only thing I really know to do about them.
If you are still worried, then just make an appointment with your gynocologist to get checked out. Better safe than sorry, but it really sounds like you have nothing to worry about.