Depending on how you are struck the injuries can be quite minor. There’s a National Park Ranger in the US who was struck 7 times on separate occasions. If the current flowing is small and brief it may actually just flow across the surface of your body and burst blood vessels in flower like bruises but cause no real damage. If however it flows through your core it can interefere with all YOUR electrical systems like your nervous system and could stop your heart or even boil fluids or cause the air in your lungs to expand so rapidly it explodes your lungs. Not always fatal, but not to be recommended.
A common cause of death is people sheltering under trees. Tree gets struck. All the water in the tree instantly turns to steam and expands by a factor of about 10,000, so you get an explosion with thousands of shards of wood. Kablaaaaaam. Never shelter under a tree! 🙁