He was a clone, but that didn't mean he had to resemble Cal down to the last skin pore.
For every hair on your body, there is a corresponding skin pore.
A pimple is a clogged skin pore that gets infected with bacteria.
The ampullae detect electric fields in the water, or more precisely the difference between the voltage at the skin pore and the voltage at the base of the electroreceptor cells.
At times, these may develop into an infection in the skin pore (pimple).
While a skin pore is open, sweat wets a strand of vellus hair.