Relapse, need advice

Hi all, I have been clean for 8 years and just relapsed on the same drug as before, Fentanyl. I was called into a meeting with HR, Nurse Manager and Security, I finally did admit that I had been taking the wastes of Fentanyl and using it. I already completed an Alternative to Discipline with the Ohio Board 8 years ago, so I know I am not eligible to do so again. My questions are: when the OBN does call me, do I tell them minimal things, so that I do not incriminate myself and consult legal advice, is it okay to say that to the board? I do not know about a criminal charge yet, still waiting for the police to contact me as well. I had a criminal charge the first time and it was expunged, I know I can not receive another expungement this time around. Does anyone have any experience with this? Anyone been through a program and then this happen again? Any advice, pointers, tips would be much appreciated. Thanks in advance. And oh, I did submit a UDS and haven't yet heard the results back from it either.