I can fully understand why he went ahead with most of the tasks, they weren't really difficult, but I really think he should have put a stop to the hair shaving one. I couldn't believe that he allowed himself to do that for the sake of a few pats on the back and some kudos with the other housemates (and the public, although I do think he thinks he doesn't need to try with us that much anymore).
I can't think of any other housemate that wouldn't have cared about how they look leaving with a shaved section down the centre of their head.
They really all should have said enough is enough, you've done your bit now Jack. They were having too much fun laughing at him, even though he enjoyed the joke for most of it (as he was content with his suitcase of cash), I really do not see the need for him to shave his head off.
BB was testing him and his mettle, and to see if he had the spine to stand up to them (and the rest of the housemates) I feel, and he failed in that regard. I did hope he would say enough is enough, even better, that somebody else would.