There IS an event timer, but you wouldn't want to use it, as it displays a counter in the corner of the screen.
Instead, use a switch to condition whether it's displayed or not. When you want it to appear, turn the switch on. When you want it to disappear, turn the switch off. You can change the switches in your existing EV003 event.
If this is not good enough and you actually want it to fade in/out, let me know. I wrote a little script that will do that (without changing the opacity half a dozen times in a move route).