Take one unsuspecting kitty...

...cut away hair to expose lesions...

...adorn with lovely plastic e-collar...

...and apply medicine.

Man, it looks so simple in photos. My biggest piece of advice, if you ever have to do this yourself, is make sure to put the collar on before applying the medicine. That way, when (not if) she shakes her head furiously afterward, you don't end up with toxic medicine all over yourself and your bathroom.