I had a morphine pump implanted a few years ago (I'm in my mid 30's now) to help with my back pain. I'm very glad that your mom had this checked out. I'm not sure what the redness could be, but as the others posted it could have been a sign of infection. I'm glad it wasn't and hope she is doing well.
The skin in the area where the pump has been implanted has been stretched quite a bit to accomidate the pump, this could be why it's turning red on her off and on. I get some redness and irritation when they fill mine every two months but we've found that it was a slight reaction to the bedadine (sp?) and now they use alchol to clean the area. My doctor told me that one of his patients actually scratched the area raw once from the same thing. So when she starts getting her refills be on the lookout for that.
Hope things go well and that she finds a lot of relief from the pump