J.S.
Tell her the truth, and ask if there is someone else in her salon that can step in for her. Most salon owners would not want to risk losing a customer. I'm sure they will work a $ deal with you. You can also have them work together on you to make sure you like what the new stylist will do.
(And don't worry so much about the wedding day. Yes, every bride worries, but it's about the rest of your life with your Mr. Wonderful that really matters. Signed happily married for 15 yrs)