Instead of checking collisions on both sides, you could send some kind of message to an enemy from projectile about type of damage.
You can do that with Apply Damage node with your custom DamageType class assigned to it. In enemy blueprint you will need to assign an OnTakeAnyDamage event, and react to information, given through DamageType pin.
You can watch a video about this system: youtu.be/MLtDgukVG94