My .02.
Hexing should not cause stress, however, it should cause in-game consequences.
For instance, in a game I ran, a practitioner put the whammy on a bad guy's gun, but he has a mild mental consequence of "frazzled". I compelled this aspect, and while he was able to hex the bad guy's gun, he also hexed all the electrical doo-dads in the building behind him, starting a huge fire and attracting the authorities.
Almost anything can be handled via story.