Does the following make sense to mean "the wound deeply damaged to make the skin caved in ?
- The dog has a dent in its head from the disease.
But note that a wound and disease are not the same thing (an impact or disease may cause wound), and a wound is not itself damaged.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.