Breaking a Habit Since Childhood

Hi Brooke,
I have a habit of picking at my fingers. It’s an awful habit that I have done as long as I can remember starting early in childhood. I always thought I would just grow out of it but I haven’t and it is probably now the worst its ever been. I have been thinking it is like other habits that you coach us on like over eating or over drinking. I am wondering how I can apply the tools that you have been teaching us to help me break this habit. Do I start with a thought download on why I think I do it? Do models on those thoughts? Any suggestions of tools to try, what to try first, etc. would be appreciated.
Thank you!