Keep him away from the drake that got him. Watch and make sure he is eating and drinking and pooping normally that would tell you if he had internal injuries.
Do you have salt? Rinse in warm salt water then let it dry and put something like Neosporin with out pain meds or triple antibiotic
Is it an open wound? There are recipes on line for mixing salt and water so it doesn’t sting.
https://healthfully.com/treating-wounds-salt-water-4898741.html
https://www.backyardchickens.com/threads/drake-with-prolapsed-phallus.1443940/ info on Prolapse.
The other problem do you have Veterycin spray for wounds and infections this should help any wounds feel better.
I'd def keep the drakes separated so your Runner doesn't get killed they are not...