so ironic..I just bought the same zapper..and just zapped a minute ago looking for the same answer to that question..
I really dont know if the "pulsating" in the wrist is normal..
It only tingled in my wrist when i used the 2.5 and the 15 no the 30khz choice..
and am now a bit itchy too..HOWEVER..instead of using humaworm I have been using Dr, natura..so I do wonder if our cleansing before hand has something to do with this..
ugg..let me know if anyone suggests anything to you..I am going to email the vendor tomorrow.