21. Do I have to use locking mist hair spray every time after I applied the 2nd generation FULLY Hair Building Fibers?

Not really, the hair fiber clings to the hair not in the help of the Fixing spray, but the electrostatic adsorption capacity.
The Fixing spray is not a MUST.
We only suggest the customer that used the locking mist hair spray after apply the hair fiber, the effect will be better.
Bald people have thinning hair which will easily mess up by the wind so they use the locking mist hair spray to fix the hair style.  
But we don’t recommend our customer using the Fixing spray for a long time because average locking mist hair spray contains Ethyl Alcohol, Collophony and Essence.
These substances will definitely not benefit to the hair.