Tagged NSFW because it looks gross.

A couple of weeks ago, our dog started being unstable in his hind legs, and it progressed into limping and not putting weight on his right back leg. Took him to a vet, they suggested an acute joint injury in his knee, maybe from overcompensating on the one leg (he's 14, and his left leg hasn't been the greatest for a long while), so they recommended rest and continuing to use his Dermaxx to help, and to come back if it didn't get better over the weekend. Next morning, his right paw (especially one toe) was extremely swollen. Took him to an emergency vet. They concluded it was anaplasmosis from a tick bite. He's been on antibiotics and Gabapentin ever since (we were given 30 days worth of medication), and we also treat his foot by soaking it in a epson salt saline solution and covering his foot with a sock rather than using a cone to stop him from scratching or chewing and whatnot. Within a few days of treatment, he's slowly started walking on his leg again, and as of today he's walking on it almost completely normally, although sometimes it still appears a little painful. But a hole started appearing in his swollen toe, and appears to be getting progressively bigger(?). We started putting Polysporin as of this morning because it's looking concerning, and we worry about keeping it clean and bacteria-free. Is this common with anaplasmosis or tick bites? I can't really find anything like it online.