"Damage screen" remains always
My Screen is always like this, even when just standing for long time:
Try using a bandage or medkit to heal your self. I suspect you are under the impression that you heal automatically in this game. This is not true.
Open the weapon/item wheel and select the medkit/bandage. With it equipped, use the item like you would a grenade. If you don't have any, you can find them by searching bodies, or searching around the map.