Am I Cursed- Colour Problems!!!!!!!

Hi,Well I'm a hairdresser & I can't work this one out, problem 1- even Joico's Verocolour (permanent) fades out showing grey after 6 days & I use products for coloured hair, No 2- I have been using Demi's for years as in Wella Colour Touch/ Kadus/ EQ & Joico, today I attempted a root re-touch with a universal activator & within 5 or so minutes my scalp was burning like hell!!, I have never had this problem in the 20 years I have been tinting my hair, has this happened to anyone else or am I cursed to become grey!!!!!, the only other thing I can think of is Nioxin that I used 2 weeks ago made my scalp itchy & sore- maybe I should have waited a little longer before I demied my head, I really do not know, as I have only come across this when using Bleach & high % peroxide (when I was hairdressing In Salons), & yes I do all the allergy Tests, help??Simone.(C). ;)