As Ivory said, ask a posek. Please do post the answer, though.
ivory:
“If a man gets white hair at age 22 for example, how is his date fooled if he dyes it darker?”
It looks as though he has dark hair. If he will not be
allowed to continue dyeing his hair after the marriage,
he will not look the same as he did while dating her.
barlev: Wearing a toupee will be difficult with tefilin etc, but I assume it’s also ?? ????
Google finds discussions about toupees and tefillin, but
I see no mention of a problem with wearing them.
Perhaps, Barlev, you should refrain from assumptions in future.
Also, the OP knew that there was an issur for men to dye their hair – otherwise, why would they ask if it was allowed under certain circumstances?