Pls help..strange cut

My cat came home from surgery last Wednesday, and the vet said she had a hard time inserting an IV. He has both forearms and a leg shaved, where the vet tried to insert an IV. I noticed that he had what looked like a piece of feline pine (a yellow pellet) stuck to some fur under his forearm. Today I took a closer look, and it was still there. I soaked it in witch hazel, and it eventually came off, and underneath was a cut. The "pellet" wasn't actually a pellet; I now think it was a scab. I've never seen a scab like that before because it was literally growing out of him and looked exactly like a pellet. The cut looks somewhat like someone scooped some meat from his arm (like a little gaping hole). I washed it with iodine and put some antibiotic ointment on it.

Does anyone know what this is, or what may have caused it? Should I do anything else to take care of it?

I would call the vet to ask about it. Is it near where they finally got the IV in? It could have been where he was restrained or where the IV was taped down and tore the skin when the tape was removed.

You definitely need to get this tended to. I hope the cat will be okay.

I would certainly call the vets and find out. It almost looks like it could have used a couple of stitches. I don't understand why they didn't make you aware of this area if that is where the IV finally went.

That's really strange. It almost looks like it was abscessed or something. Best to get it checked out so it doesn't become infected.

Thanks everyone for the replies and the help! I just wanted to provide an update. I'd been soaking his wound in water (with iodine, and later with epsom salts), and eventually a strange "splinter like twig" was revealed sticking out of his wound. I pulled it out. I think he had an open wound somehow, and while scratching his sisal post, some plant material pierced into the wound and buried into him, to the point that it was not visible. The vet said the strange "pellet like scab" was his body's attempt to expel the foreign material, which she thinks is plant based (likely a piece of sisal). Anyways, after that came out, his wound is now healing nicely.

Thanks again everyone for the replies!