
I have had mine pant for upto 2 weeks after, not just the afterpains but also as you said the heat the last few days wont help.
Are you using a heat pad, if so try to place it in the centre of the box as most bitches lay against the sides of the whelping box and therefore she wont be laying directly on that as this will make her too hot along with all her babies snuggling up.
As long as she is well and eating then just keep an eye on her, if you are really concerned have a chat to your vet but i would imagine it is all ok.
Good luck with your mum and babies :)