I've just done a week's work experience at a hairdresser's and both my hands have come out in a horrible rash. My GP says it's "severe dermatitis". Do you think I should go back for the second week?

No, I don't. Hairdressers are 17 times more likely than other woman to get dermatitis of the hands because of the chemicals they come into contact with. So this probably isn't the ideal job for you.