Few years back I was ripping out base boards in a house I just bought and found mold behind the base boards. The areas were minor, maybe a couple of inches wide spot. I started wondering what was causing it. The walls looked fine and the wallboard was solid. Then I noticed the wallboard was damp behind the baseboard. So I started cutting open the walls and found the installation in the walls was soaked. Turned out the siding on my house was not properly installed in the front corners which had caused water from outside to get behind the siding. Had been going on for years. The water had soaked and rotted away the wood paneling/wall of the house allowing water into the walls. Several wall studs were rotted and had to be replaced. I literally had two sections of wall removed from my house and replaced. You could walk from my front yard into my living and dining rooms without having to use any doors. The leak was almost at the top of the walls but had no sign of this from inside of the house or the outside.
My point, you need to figure out what is causing the mold, where the water is coming from. It could be a much bigger issue than just the little spot of mold you found.