Josie is allergic to creams. For some reason, she develops rashes when she tries to apply even a drop on her skin. So instead of cream, she bought an acne face wash instead. She has acne but is slowly solving that problem of hers. She immediately sought help when she realized she has some on her face.
That’s how you prevent something from spreading. You immediately get help or do something to stop it. Just like what Josie did.