I know that I'm new here, and this is only my second post, but I had a very similar procedure performed on me about five years ago. Most likely your mother had laparoscopic surgery. Yes, despite medication, the abdominal area is going to hurt pretty badly for awhile. I know it did for me. But have your mother take it easy with the movements. Within two weeks time she should be on the mend.
I don't know the nature of your mother, i.e. is she very independent and like to do things for herself, etc. That is, is she willing to take it easy and let others do things for her while she recovers. Thankfully your mother has two months, I only had one. But at the end of that one month I was moving around a lot better, although I still had to be careful.
Bear in mind that she shouldn't lift too many heavy objects or twist at the waist too much. Otherwise she'll feel a slight pinch in the abdomen, letting her know to ease off. But if after two weeks she still has unbearable pain, then yes, have her see the doctor again. I hope this helps. God bless you and may your mother have a good, healthy recovery.