He reflected himself in the mirror.
I wrote this myself. Can you explain what this sentence means? Is this correct or incorrect?
It's probably clear what it is supposed to mean, but it is not grammatically correct. The subject of reflect must be either be a beam of light or the reflective object (in this case the mirror), for example:
The mirror reflected his image.
You could make this into passive voice so that his image moves to the front of the sentence, and then he can see the image.
He saw his image reflected in the mirror.
He saw himself reflected in the mirror.
This uses passive voice.