I've had 9 sessions of diode laser hair removal on my pubic hair, why does the hair keep growing back?

The treatments may not be strong enough.  I suggest you have your treatments with a Dermatoligist rather than at a spa.  We sell 6 session packages and that covers most people.   Occasionally some one needs an extra treatment or two. As the hair gets thinner the laser needs to be set higher to treat the finer hairs that result from treatment.

It is important to note that this treatment should be referred to as permanent hair reduction, not permanent hair removal and outcomes vary from patient to patient. There are numerous things to consider in the consultation process, for instance what color is the hair being treated (most lasers will not treat white, blonde or grey hair and reds might not be as effective) what is your skin type, etc. to determine which laser is best suited to treat each patient.  In a series of 6 treatments spaced 4-6 weeks apart (this is the recommended treatment spacing for your area of concern) you can typically expect an 80% reduction.  Again, please keep in mind that each person responds differently and may need more or less than six treatments.  

Thanks for your question.  It sounds like your provider has no idea how LHR works.  The gap between treatments should be whenever you need to shave regularly.  You have probably been waiting too long at 3 months between treatments and not getting all of the hair that is actively growing.LHR treatments deliver a burst of energy to the hair follicles that are actively growing.  The energy destroys these follicles ability to produce another hair.  The hair shafts in those follicles will release and fall out over the next 1-3 weeks.  Other dormant hair follicles start producing hair every day.  It takes a series of at least 6 treatments to get most the hair growth.  In order to avoid surface burns, we have our patients shave before LHR treatments.  You must not wax or pluck during LHR treatments.  You can shave at any time you wish between treatments.  Best of luck.