Lightning strikes can cause various symptoms. They usually loosen some bark, which hangs on the tree in strips. The amount of bark loosened will depend on the severity of the strike. Sometimes only a narrow strip is loosened; other times a large portion of the circumference of the trunk is affected. A tree struck by lightning may show no symptoms until it dies mysteriously days or years later. The lightning bolt may pass through the trunk and seriously damage the roots.
Remove loose bark and broken branches as soon as possible after the strike. The tree may show no other effects or it may die suddenly within a short time. All you can do is to reduce other stresses, such as dryness and pests.