My tree during the time it was producing fruit, the leaves started turning yellow, then brown then off the tree. I thought that it was due to the time it was bearing fruit. Now the tree has only a few leaves which are very small and pitiful looking. When I was cutting a limb off which extended much longer than the others it started dropping. Before I could get a grip on it, the limb tore from the trunk. I then finished removing the limb and tied up the injury. I am wondering if this caused the problem that later happened. I do not have a way of making a picture (no smart phone) and my camera is on the blink. I can try to take one tomorrow with my old cell phone, but it tkes small picturees.
It sounds like the tree was stressed at some point, it may have been due to water issues.
The tree's bark injury, though on it's own shouldn't be an issue, but combined with a stressed tree could cause further issues.
Most bark injuries should heal on their own, so avoid covering the wound.
Review the care needed for Loquat Tree's in the link below.