I personally would have never done that unless I was trained in proper dosage and dosing. I also would not have given an oral antibiotic to a reptile, not knowing how it could affect liver and kidney function. Baytril, with is a very common antibiotic used to treat certain forms of RI, is injected. And last but certainly not least, I would never pull something out of my medicine cabinet and given it to my snake without better guidance than something I researched on the internet.
Those are my thoughts, and remember, you asked for them.
Now, does it seem like you may have gotten very lucky? Quite probably so, but that does not mean it wasn't very risky, and we have no idea of what the long term effects of oral dosing might be.
Trust me, I understand being broke FAR better than most, but I also understand about programs like CareCredit and Veterinary Assistance Loans. Information on which, can be researched on the internet...