Usually comb damage doesn't require anything antibiotic related. Some antibiotic creams also contain things that aren't good for chickens; some are safe though. But this type of situation shouldn't need it either way. Sometimes disinfecting with a product like vetericyn is worthwhile if the wound is fresh, but if it's dry it may not do much.
A lot of minor damage like this heals easily without intervention. Combs also bleed a LOT for a small amount of damage, so all it can take is one decent bite to make it look like something much worse happened. If the bleeding has stopped it will scab up (some areas will turn black) and the scabs will fall off in time. The hen can be reintroduced in the morning as long as there's no ongoing bleeding. I would watch for a while if you can to see if you've got a bully that wants round 2 - in which case it's the bully that needs a time out to help reset things.
