[move]Ace support[/move]
The script forum is for presenting scripts you wrote yourself. However, I'm moving this to Ace support instead of script support, because I don't think you'll need a script at all, but are under some misconceptions and most probably this can be handled by pure eventing.
First, item use is instant - there is no time directly involved, so any event can only be either before or after the item use, never during. That is why such a script call simply doesn't exist.
If the item causes a time-lasting response like adding a state for some steps or turns, then you can check the presence of the state directly by conditional branch - no need for a script call
As an alternative, an item can call a common event on use - and you can use that event to handle any specific interaction that might be needed at this moment, including map interactions - again no need for a script call.
And third, if you have an event that need the item used as a payment, there is a much better way of using the select key item command to select and pay with that item instead of having it used on map.
If what you want is something else, please describe what you want to do instead of how you want to do it (the "check for used item" is how to do something, but you never described what that something is that you want to do in the game), then we can probably point you to the correct solution.