Although earwigs are called earwigs the earwig does not lay their eggs in your ears.
The earwig is capable of climbing in your ear which they might do but they will not lay their eggs in your ears nor do the earwigs feed off your brain.
Earwigs and other insects have no way of getting into your brain through your ear so there's no need to worry about that.
The earwig can amazingly live for quite a long time without any food or water.
Scientists have put earwigs in petri dishes and left them without any food or water and the earwigs have survived for as long as 3 months and longer.
So that means that earwigs can live without food or water for at least 3 months and sometimes longer.
The earwig is a pretty tough insect and can adapt and survive for a long time.
So out in the wild an earwig can go a long time without food or water and survive.
That is longer than any human can go without food or water before becoming dehydrated and then dying of hunger an dehydration.