Hi,
I’m looking for a way to make the player take constant damage while not in the proximity of a light source; it’s a top down game - so as far as I know it can’t be camera based.
Any ideas would be helpful! 
If you subtract the player pawn world location vector from the lights world location vector, you can then drag out a pin from the result and use the vector length node. This vector length node is a float with the length of the vector (the distance between the two vectors) you can then check if this float is greater than another distacne float, say 500 . Anytime the player is more than 500 units away from the light this will return true.