Hi, bwb
As I understand it (and I am not an expert), the nurse should not give you medical results unless you have a medical POA for your mom. In any case, the doctor would likely be the one to give results.
If the biopsy results are negative, the doctor will still likely want to see your mom to verify that the biopsy site is healing properly.
Does your mom like movies? Maybe you could both go to see one over the weekend. Waiting sucks, but it helps to keep busy!
Best wishes and fingers crossed for a good result.
Maria