Considering how much pain you already experienced, the more recent pain isn't too bad. You still feel good overall. You feel more concern than you do pain. What will your future be like if you stay a dog? What will it be like if the spray wears off and you become human again?
The family that adopted you already left for their home. You understood enough of the human conversation to figure out that the family had only been there on vacation and now you were going to be shipped by air to their real home far away. You figure the family must be well off if they can afford to ship a dog without worry about the cost. You even overheard that they have a beach house as well as having a home with a large private yard?
So you stay at the kennel a few more days until the flight can be arranged. This gives you time to wonder if you are turning fully dog or not. You've found it difficult to read. You've found it difficult to understand some human words? For example, when your new owner spoke about sales tax, you couldn't remember what the word tax meant? Then again, you don't care. You remeber that as a human, tax was important, but your dog mind doesn't care. Much about how you think is like a dog now and not like a human.
However, you feel sure that you won't completely lose your humanity. Reading may be difficult but if you work at it, you can still make out a few basic words. You still know what a stop sign is. You're not sure if you'll recognize the color red with your new dog vision but you can still recognize that word and other simple words.
Also, you still remember your life as a human. Many of those memories don't make sense to you now but they aren't forgotten. You still know that you were turned into a dog by a spray that you sprayed yourself with. You dropped the can and that is why you don't think you completed the job of turning yourself into a dog. You don't understand why you changed yourself into a dog in the first place but you do remember thinking it would only be temporary, whatever temporary means.
You pant for a while and then get a drink from the dog bowl. No sense worrying about it when there's nothing you can do about it now.