every stylist will say no as well as every handbook. Doing it anyway will be your choice, as it was mine. I did it myself, so I didn't care. Nothing happens. One person who describes her hair as on the thinner side said she noticed a slight dent, but just flat ironed it out. It really only matters if you got thi streatment to straighten your hair, so a slight dent might bug you. If you got it to smooth your curls, then it won't effect your results. I've done it like 10 xs now, and I've never seen a dent. You really have to make the choice.
Otherwise, there really is nothing to do during the wait.