I am a personal trainer so this is my advice.
Do NOT do bar hangs! You will make it worse. You need to ice it,keep it wrapped with an ace bandage or the like,and rest it. Do not stretch it either. Do not shoot a bow.
After it heals in a few weeks you need to take a softball,lay on the floor and roll your forearms,biceps and triceps on the ball. This is called myofacial release and is a self massage. Do it daily.This will get rid of all the muscle knots,or trigger points, you have farther reducing pain and preventing any more injuries. Then you can start to gently stretch your forearms,shoulders and triceps and biceps.