Cats are diligent groomers. Any ointment or treatment that is placed on a cat’s skin has the potential to end up in its mouth. I rarely recommend topical medicines to help scabs heal in cats.
If the scabs are surrounded by red, irritated skin then oral antibiotics may help with healing. If they are not, it generally is best to let the scabs heal naturally.
No matter what, I recommend that you do some more investigation into the cause of the scabs. When cats bite each other around the neck, abscesses (areas of infection filled with pus) may develop. Hair may be pulled out. But cat bites almost never lead scabs.
In other words, I doubt that the biting cat is causing the scabs.
Scabs on the necks of cats most often are caused by allergies. Although there are millions (literally) of potential allergens in the environment, fleas are the prime offenders. Allergies to fleas cause a syndrome called miliary dermatitis. Miliary dermatitis is characterized by scabs on the neck. Most cats with miliary dermatitis will not have visible flea infestations.
I recommend that you tackle this problem with a high quality flea preventative. If that doesn’t do the trick, a trip to the vet is in order.