Sounds like an infection get her into a vet as soon as possible and they will put her on a course of antibiotics to clear it up.Either way you need to get her checked out as this is not normal.
Mastiffs are a wonderful breed so noble and kind, you will come to adore this speciel girl.I was blessed with a wonderful Male Mas(Butch) for 10years loved him to bits.
Please let us know the outcome
I don't think she should be bleeding now. I would take her to another vet, to get her checked out. There could be some slight bleeding just post-surgery, but after 2 weeks...? I don't think there should be.