My dog got spayed 2 months ago and her outer incision healed well but now she has a purple bump where it was and the vet is not educating us on what is wrong. Any idea what is wrong and how serious it is?

Take her to a vet that knows what they are doing! This could be very bad. It could be internal bleeding. I would almost say go to an emergency clinic... this could get ugly and very quickly!

I am in agreement with love a bull, I would take her to another vet.
(cute avi by the way love a bull)

A good vet will explain what is going on and exactly what is wrong, not keep you in the dark to worry.

Spaying typically takes 6 weeks to fully heal.. the stitches come out after 14 days but there is still a lot of healing to do... seeing as how it's been 8 weeks I would guess that it has actually healed but this lump may be a cyst or infection stemming from the wound.