The laser treatment only kills the follicles that are in the active growing stage. That is why you need more than one treatment, because not all follicles are growing at the same time. The ones that you have to shave between treatments are the ones that have not been killed from previous treatments.

You usually have about 2-4 weeks of time after a treatment where there is no growth, because of the growing cycle. The active ones have been killed, and the next group of follicles don’t become active for a few weeks. And shaving is the only hair removal method allowed, you are not allowed to use anything that dissolves the hair, such as Nair, or that pulls it out, such as waxing or plucking, because it disrupts the growing cycle.

By the way, where you are being treated will determine how many treatments are needed. The chin is the most difficult to treat because it is influenced by hormones. I’m about to call for my 8th treatment.