Mark on plant

I see marks like that on young plants. the only reason you'd be concerned is if it seems like something is "tunnelling", then you have a pest, but these discolorations are perfectly normal on an early leaft, which this looks to be. get the water off the leaves if any drips one them. Water is for roots. foliar spray is for OCD with zero benefits worth the effort and tons of potential negative repercussions. statustically not a wise thing to do, like hitting on "20."

looks like a water burn.. try to only spray before lights out.. Spraying during high light can cause this. The water pools on the leaf surface and creates a "hot" spot from the water reflecting... Like magnifying glass and using sunlight to burn ants.