Let's give it a try:
I have an idea inside me
A watch talks about the idea of counting the time before the world ends.
But it'll never come to be
But the end will probably never come, so it is "doomed" to count forever and the idea will never achieve its final aim.
The idea is (usually) protected, but is it for me or for you?
This sentence is hard to explain, does it talk about the physical protection the watches have to be durable? Or is it about the fact that time-tracking is so advanced today (we can even count microseconds) that it is impossible to make a mistake? One way or another, is this protection meant to be for the watch (to give meaning for its existence) or is it meant to exist for us, to be able to schedule things, count ageing etc.?
A simple flick of your wrist
And I might just die
You check the time, you then turn your wrist and although the watch is still there and you carry it, it just counts uselessly. No one pays attention to it, it is like it's dead.
But another flick can bring me back to life
But then you literally flick your wrist to check again your watch and this adds meaning to its existence, it "resurrects" it.
I'll help you to see in your darkest hour
Play with the words, as the new watches have light to show you the time when it is dark. Also, when at night, we lose track of time, because there is no sun...
But when it's too bright, I lose effective power
... but during the day, you can approximately tell the time by looking at the sky and the sun's position. It is also more difficult to use the watch (?).
Still, I love me for what I am
The watch loves itself as it serves such an important purpose and is indispensable, even with the smartphones taking over, but do we? Do we enjoy our lives as time goes by, does the time-tracking makes us more anxious, does it even have a meaning any more to count the time?