Based on your description it sounds like it wasn't even 1% your fault.
1) You didn't know. Therefore not your fault.
2) You usually Google, but this time you didn't due to meds and pain. Therefore not your fault.
3) You trusted your doctor, like you're supposed to be able to. Therefore not your fault.
There's nothing to own up to. You were a character in the story of what happened. Not the cause of what happened.