Hi,
Hindsight is a bugger.
If you had taken the injections for the infection when offered you might well have avoided this situation. This would have worked out cheaper than having a second consult and still having to pay for the injections anyway.
Peroxide isn't the best thing to use as it damages healthy tissue as well - a diluted betadine solution would have been better.
But for deeper infections neither will really do much. You might want to get the vet to culture the infection and run a sensitivity test. It will cost slightly more initially but it should mean you end up getting the right antibiotic to cure it. They usually put the snake on a broad spectrum immediately until the test results come back.
dr del