Pre wedding Spa Day

I am getting married in October and my lovely MIL is taking me to a spa day in September. When she initially agreed the date with me I was clear of my period but a recent late period means I'll be on my 2nd day of my period. I don't use tampons and I'm really don't feel comfortable asking her to move that date especially when it's probably all paid for and she's doing such a nice thing. However I am dreading wearing a bikini, trying to get a massage, I won't be able to go into the pool etc. I just don't know what to do! If this period didn't stray I wouldn't be in this mess. Any suggestions