You're a full dog. It's hard for you to concentrate and understand what your brother is saying. After a few seconds of collecting your thoughts you begin to make out what he's telling you. "So if you're a good dog for the next week or so then maybe I'll go to that shop and get you changed back, maybe". He seems to be mocking you in a way, though you aren't sure how. At least you now know that he changed you...wait he changed you, HOW COULD HE!
Your brother changed you into an animal, but, as much as you hate it, he's your only hope you have of changing back. You need him to do it fast too, before you can't concentrate on keeping your humanity any longer. "I'll treat you like a dog and in return you will have to act like a dog." he states. This will make keeping your humanity much harder. "Oh, and I seriously am signing you up for the k-9 unit, so be ready for it." he states before grabbing a towel to dry you off. This will be an long week for you, a long, awful week.