Help with makeup dependency?

My mother-in-law is taking me and her daughter to get facials tomorrow and i'm completely freaked out about it. I have never had one and from what I have read seems like you shouldn't put make-up back on for quite awhile. I never go anywhere without makeup because I hate the way I look without it. So I am worried about them seeing me without it on but to make matters worse, they want to go shopping and have lunch afterwards. Neither of them usually wears much make-up so the idea of going out without any is nothing to them, but it scares me to death. I know I have self-confidence issues and my husband tries to tell me that I look fine without it but I think he feels obligated to tell me that. I have this fear that I will see everyone I know and they will all notice how horrible I look. I'm confident with make-up on, but I have never not been able to wear it for the past 10 years. Any ideas to help me not stress out so bad?