How shall I treat my injured Oranda on its Wen?

While I was changing the water by siphon my Red cap oranda was caught in the sucking pipe head in its wen (cap). When I blew water in the reverse direction through the pipe, the fish was released. But he has developed a deep injury in its wen. He is bleeding (Seen by blood clot) on its wen. I have isolated him in a treatment tank adding Neutralised Flavine (Rid All General Aid). I don't know it is free blood or blood clot. What antibiotics shall I give him and for how many days? Please suggest the name of any human-antibiotics as Maracyn is not available here. Thank you.