is a correct diagnosis!
Please dont worry mumps will take around 7-10 days to resolve , and she will do fine
Actually there is no need for the antibiotics at present since it looks like mumps , however i would still like you to continue them as we dont want another super added bacterial infection to come !!
She should finish the course of augmentin
and take it for 7 days!!
Your child should have been immunized for mumps by now and it is unlikely that he will get the infection from her so you dont have to worry.
The pain while chewing is typical of a parotid swelling as seen in mumps and will resolve once the infection subsides.
Please ask her to take rest and drink lots of fluids.