Im a type 1 diabetic... is it unhealthy to have 1 pill of hydrocodone for pain relief?

No: If it is prescribed for you. Without knowing the rest of your history, nobody can give you good advice about its safety. This is in part because for some people, the first one leads to another, and to 5, and then to 10 etc etc, just like alcoholic drinks may for alcoholic people. In general, one vicodin/norco etc. Is not going to cause any harm to a diabetic.