After the dampness is eliminated, you can start getting rid of mold (only after that cosmetic work will go, where the most pleasant point is the choice of wallpaper). First, washed the place where the mold developed, then cleaned, completely removing it from the surface of the wall, and then dried. The next step is chemical processing to kill fungi and microbes and prevent their subsequent appearance. However, caution should be observed with them, as they are poisonous, and after processing it is necessary to ventilate the room. But when there is no visible flow and traces of mold, but it is clearly felt that the apartment is too moist — it may be worth acquiring a moisture meter to establish it with it, is it really so. In the case when the dampness is really large, you can drain the air with a moisture absorber, or maybe it will be enough to simply ventilate the room regularly.