Dixie,
My first dog suffered from Mange sometimes too. There is a dip product you can get at the pet store that you mix up with a gallon of water yourself. It cost about $15.00 and gives you about 5 dips per bottle. It works just as well as the dip at the vets for a lot less money.

It was great of your Grandma to help you out! If you try the store dip then you can use the money Grandma paid for some other vet service. We all know how expensive trips to the vets are!