It's unfortunate that you didn't read the instructions, too much of the stuff and it can leave your lawn looking a right mess, but it is salvageable. If you haven't done so already, give it a good watering ASAP.There's another thread here which may help https://forum.gardenersworld.com/discussion/1039591/evergreen-4-in-1
That'll be it. You need to spread feed & weed stuff thinly and evenly, and no more than the instructions say. Keep it watered and wait. It might grow back given time. If not you'll need to rake out the dead bits and reseed the bare patches.