The black and the white

Maggots are used in medicine to eat away dead flesh, leaving the wound clean and ready to heal. Disgusting but useful.

Leeches have been used in medicine to drain blood, to no benefit and often to the detriment of the patient. More recently, they are used for the anticoagulant properties of their saliva to keep blood flowing. Disgusting but useful.

I am eaten by maggots, sucked by leeches. My disgust is not useful. The wound is fresh, I bleed; when does the healing progress?