You'll be okay waiting until Monday, so don't worry about that part. It could be a "hot spot" - does it look like one? It's hard for me to tell from the pics. But if it's red, flaky, kind of scabby - then it's likely a hot spot, which is really just another name for an infected skin area (ie, pyoderma/bacterial infection). If you think it's that, put some antibiotic ointment cream on it a few times a day.
If it's an actual hard lump, it could be a cyst or something, many of which are benign.
Also check her armpits, inside legs, tummy, near base of tail etc for any other red areas that would indicate a more widespread pyoderma.
__________________ ~ A friend told me I was delusional. I nearly fell off my unicorn. ~
°¨¨¨°ºOº°¨¨¨° Ann | Pfeiffer | Marcel Verdel Purcell | Wylie | Artie °¨¨¨°ºOº°¨¨¨° |