I've had BV twice, both times before I was working as I overly clean myself and I think my body is just used to it now that I don't get BV........watch this space, I will get it next week now that I've said that

Anyway both times I took medication for it and it cleared up within a few days.
I know you don't want to loose the booking but if he's a regular he may rebook for another time, tell him you've taken your period or something.
I definitely wouldn't work with BV, it's unpleasant and not what the client expects when handing over money like that, especially the cost of an overnight.
I had to cancel an overnight booking a few weeks ago because of my period, although we were both disappointed, men are more understanding than we give them credit for on lady's problems and they know that it's something we have no control over.
xx