Hoping to get some advice from those who dye their own hair. I had a groupon type voucher for highlights recently but got to the hair salon and they apparently had had to cancel my appointment because nobody was available to do it (nice of them to let me know 
) I was pretty ticked off (and not impressed as the salon reeked of cigarette smoke anyway) so went to Boots and got a home dye kit to lighten my hair. It doesn't look bad, but not nearly as light as it should have come out. So I'm wondering whether it'll be ok to get another one to try again or whether that will just fry my hair and I should leave it be? I'm used to dyeing my own hair but have never felt the need to dye it twice in quick succession. Hair is quite fine, slightly weak, but looks and feels ok, not straw-like or anything! Shall I do it again or leave it?