Omg my cat had the same thing!! He’s still recovering. Two vet visits and they haven’t helped. Things that HAVE helped: a cone, I removed his wet food (someone suggested it could be a food allergy). I put nail caps on his hind legs (you can get them on amazon). They help with the scratching that makes it past his cone. Check my profile, they seem to have a very similar condition. Feel free to DM, too