Hard to see anything from this picture, but yeah you can't really fix damage to trees, only let them heal themselves. All you can do is protect it and give it all the resources it needs to heal (water, fertilizer, light).
if the other side looks the same, it's not going to heal. only the outer layer of a tree just below the bark is living, the inner wood is structural and no longer alive.
Hard to see anything from this picture, but yeah you can't really fix damage to trees, only let them heal themselves. All you can do is protect it and give it all the resources it needs to heal (water, fertilizer, light).
if the other side looks the same, it's not going to heal. only the outer layer of a tree just below the bark is living, the inner wood is structural and no longer alive.