Dry to scab up is old, outdated thought. Keeping covered and moist speeds healing. Vaseline or Aquaphor. Wasn’t the Vaseline that irritated it, Vaseline is about as inert as you can get. Might have been reaction to tape or the surgical scrub they cleaned the skin with before the biopsy. Perhaps even the sutures but it wasn’t the Vaseline.
Here’s wound care information after biopsy from American Academy of Dermatology:
And yes, about this kind of stuff, doctors do know everything.