mold behind drywall near plumbing 38

https://wiki-triod.win/index.php/How_Gateway_Water_%26_Mold_Handled_Hidden_Mold_Behind_Drywall_After_a_Plumbing_Leak

After noticing a musty smell in the bathroom, I pulled back a corner of the baseboard and found black mold creeping up the drywall behind it, right where the plumbing runs through the wall. The moisture from a slow pipe leak has clearly been trapped in there, creating the perfect damp environment for mold to spread, and now I'm worried about how far it's gone inside the wall cavity.