How do you make permanent ink for skin?

get the offending marker and a cloth ,put the cloth immediately after the point of the pen and draw on the originally marks wiping at the same time as you are marking.

the idea is , the chemical that keeps the ink wet in the marker works on the marks on the skin or furniture or whatever, BUT, it has to be wiped at exactly the same time AS YOU ARE MARKING IT ,so you are marking and wiping at the same time.