Don't worry about it
(If it's just a single square as Modern Algebra asked)
Go into common events in your database and make a new common event. Call it 'Exclamation" or whatever you'd like. Set it to parallel process, and no condition switch is necessary, so leave that blank.
In contents, all you have to do is make the event "Show Balloon Icon-Player, Exclamation". Simples, yeah?
Then the spots where you want the exclamation to pop up, you just set an event
>Priority-Below player
>Trigger-Player Touch
And in contents, have it call a common event. Call the event 'Exclamation' (or whatever you called it) and that's all you need to do. Now, when you walk over the event in your game, the bubble will pop up and disappear when you're not on it.