How can I make the pains of tendonitis subside?

I’ve had tendonitis in my right hand for months now. I didn’t know I had it until a few days ago when I saw a doctor. I thought it was just a sprain.
Anyway…
It hurts so much, and no matter what I do, it wont stop. I haven’t used it at ALL and still am not, but it just wont stop hurting. What do I do?