I don't like to wrap a cut like that... It seems to heal slower. But if you leave it unwrapped, you have to clean it more (at least twice a day, but 3times is better), and you need to really scrub at it. And also you need to keep a ointment on it that will keep flies away. I can't remember if furazone does.
But I think why ur getting a little worried is b/c it looks bigger now. Well, yes...for some reason when it heals from the inside out the opening will become a slight bit larger, but as long as there is no smell, colored fluid leaking, or red hot flesh, ur ok. After a point you will want to let it dry up a little. You can use sulpher on that. There is a grey powder tract supply has too, but I can't remember the name.