Although DIY projects can be fun, cheap, and educational mold is not a good DIY project idea. Although there are tons of tips and tricks on how to "kill" mold, it may not always work. Wiping mold may look like it has been properly treated but the spore count can still be fairly high and can grow back. SERVPRO of Mar Vista suggests removing any pores material that has come in contact with mold. Your best option of getting rid of the mold on your drywall is to just cut out the area. There's nothing like a safer treatment for mold than just removing the source. If the mold extends over to the framing of your house, the area would need to get wiped down, dried out, and grind to make sure the layer of wood that had the spores attached to it is completely off. Mold can be very tricky and unpredictable. It is okay to ask a professional to come to take care of this DIY project.