#here im giving you an example of how you can change canvas text, u have to use itemconfig :)

self.canvas = Canvas(root, width=800, height=650, bg = '#afeeee')
mytext = self.canvas.create_text(100,10,fill="darkblue",font="Times 20 italic bold",text="Click the bubbles that are multiples of two.")
#here ill edit the text.

time.sleep(1)

self.canvas.itemcongig(mytext, text="text has changed!")