A year or

A year or so ago I got root treatment done on my front left tooth as it was causing me a lot of pain and discomfort, after that over time i noticed the tooth turned a dull grey colour. Now my front right tooth is now starting to have the same problems and causing me a lot of pain and I am having to return and get root treatment on this tooth aswell, I am worried that this will be the same and start to discolour like the other one. I am really self conscious about this and was thinking about going for veneers as I have now been left with my front two teeth very discoloured due to pain in my teeth resulting to root treatment. I was wondering am I eligable to get this done on the nhs or would it have to be done privatley?