Not to worry. The tree has or soon will compartmentalize the damage (CODIT). Over time new wood and bark will grow in from the sides and it may eventually close completely. Of course, the more foliage there is above the wound, the faster this process will proceed.
When bark is damaged exposing the xylem (wood) there are some cambium cells or xylem initials left on the surface. If covered immediately with polyethylene (e.g., HDPE wrap, visqueen), silicone film, or any other film which is a moisture barrier that transmits oxygen, the tissues will regenerate quickly from those residual cells. But after a day or two they will be dead and covering the wound will no longer accomplish anything productive.
So, I suggest you leave it be and do not reduce the foliage on that stem.