As long as the script is in your name you have legal cause to take the drug. There's no law or rule that says you have to ingest all of your meds within a certain timeframe (antibiotics excluded for obvious reason). Also, hydrocodone is an opiate and would show up on a standard drug test as such, or even heroin. I definately recommend you disclose your hydro use to the nurse or doctor administering the test. Bring the script bottle with you ot show that you are a legitimate user.