You have already treated it with polysporin and it still hasn't responded to treatment. Also, you are still concerned so just take her to the vet. Maybe it isn't serious but let the vet be the judge. Why keep guessing? That snake is beautiful, just make a appointment. If we, as humans cut ourselves on metal it usually requires a tetanus shot or a booster at the least. Keep us updated! Don't forget to donate to USARK so we can defeat that "lacey act". Stay in peace and not pieces. Good luck.