Let's say I build up charge on my body by rubbing a balloon on my head so now I am positively charged. Now if I touch a metal object an arc will jump hence discharging the charge I had built up. So for this arc to jump (current) there must have been a potential difference between me and the metal object. So by definition since $V=\frac{W}{q}$ some work must has been done on the electrons when rubbing the balloon on my hair? But specifically, what work have been done on the electrons in this situation?