Male cat chewing skin off

Question
My 1 1/2 year old fixed male got out and was in a scrape with another cat. He appeared to have healed from bites, but a week later has begun chewing the fur and skin off the site. What can I apply topically that will keep him from further chewing. He is eating well and acts fine.

Answer
I have to recommend getting him to the vet.  It could be he's got abscesses under the skin that aren't visible.  These can become very dangerous if not treated promptly.  The bacteria can spread to the blood and infect the heart, kidneys and liver, leading to deadly organ failure.

It's also possible he's got a staph infection in those areas now.  This is pretty common with superficial scratches and bites.  It's intensely itchy.  And staph is another bacteria that can infect the internal organs, so this needs to be treated right away, too.

Let your vet know this all started with a fight.  An antibiotic may be recommended in case of infection.  And a steroid cream to apply to the area, or a steroid injection, might be given to reduce inflammation and itch.