It's used once a day, at night, and I use about a pea-sized amount. I've found it's pretty thick, almost pasty, and I feel like I have to use a bit more to get it to spread evenly over my face.
I have just less than 3 weeks left in my 8 weeks, but I am glad to hear your doc said you could do 10...I might keep going for a couple more weeks to get all I can out of it!