Do I need a root c?

It is not unusual for a tooth to ache for several days after such extensive dental work. As long as the pain is getting better, there's a good chance you won't need a root c, but it definitely sounds like you'll need a permanent crown. I don't recommend root cs unless the pulp of the tooth is infected or dead, because a tooth after a root c becomes brittle and can fracture easily. It sounds like you can use a prescription strength fluoride gel to brush your teeth with. I'm surprised your dentist or hygienist hasn't already prescribed it for you.