No result after 5th session of laser hair removal, what should I do?

After 5 treatments of laser hair removal, you should have seen some decrease in hair in the area of treatment. Have you looked at your before photos? Any difference? Have you been getting your treatments 4-6 weeks in between sessions? The key to successful hair removal treatments is to have the laser treat/kill the follicle while it is in it's growth phase. If you have been doing this and keeping up with your treatments as scheduled you should discuss with your provider that you haven't seen the results you were expecting. 

It is hard to judge results without seeing before and after photos.  Most patients require 6-8 treatments to see reduction. The hairs that are killed are the ones that are actively growing at the time. The other hairs that are not actively growing will slow down and grow finer like you are describing.  For most patients of skin type 4 I would start with a Yag laser, but if patient is lighter skinned could try using an alexandrite laser.  I would talk to your treating physician to discuss you why you are not seeing the results you expected.