Just because many of us have used this product (myself included) does not mean that it's the answer to the OPs problem. It might be, it might not be. Maybe the pet needs something more.
None of us have seen what the infection looks like or know how bad it is. We do not know how long it has been going on. We do not know if the infection has spread, or even if it is an infection.
I stand firmly by my instinct here. Based only on the info in this thread - the answer at this time is not polysporin. It's a vet visit.
Maybe the answer after the vet visit will be polysporin, maybe not.
Good luck sspikey.