Hello, Loudud6409
I wouldn't worry about it too much. The ointment will take care of the bacterial infection, but it will take some time for the fur to come back and thicken up again.
It can take several weeks to see any improvement with the hair. If he paws at the ears a lot, you can get a cone collar or inflatable collar at any pet supply store.
Sincerely, XXXXX
Expert in cat behavior and health
Expert in cat medical and behavior issues.