My cat seems to have a wound on his right leg. Dry so probably ~2 days old. Anyone have ideas what could have caused it?

Male indoor cat, 3 years old, neutered. Seems kinda dry, I guess 2 days old. Never had something like that before. I dont think I have any objects lying around that would cause this. I'm out of ideas what could have caused this. Anyone might know?

Also I won't be able to go to the vet until probably tomorrow. Should I just leave it like that for now?

imgur images of cat leg