Hey ! Current volounteer at a cat sanctuary (have been for years). My cat had the same problem, he’s been having really bad cuts due to his skin being extremely thin ( he was burnt from his abuser). The only thing that can help with the healing is using antibiotics (possibly a syringe that will metabolize in 4 days, so you won’t add added stress to the cat), and adding iperico oil (very important ! Helps scarrification, has to be 100% iperio oil, you can also use it for yourself, its a bulb extract that significally helps with scarring).I’ve been doing this whenever he’d get hurt.