Help file wrote:
[Religion help] blemish
Syntax: blemish <victim>
Blemish is usable only by those who are highly favored by their immortal
patron. It is used to remove the blessings bestowed by the immortal's
(un)Holy symbol. In effect, the transgressor has been marked as being in
disfavor in his religion until he is able to remove the sin from his soul
and be atoned. Should one of the favored of an immortal be seen as
the transgressor, the matter must be brought directly to the immortal, as
no one else may blemish one of the favored.
See also: atone
At F2, a priest can create a holy symbol. I don't think it has any other application. (I hope someone will correct me if this is wrong.) Most priests are at F2, I suspect.
Most regular members are at F1 (non-priest, non-high-follower).
As I understand it, if you're a priest and blemished, you can't use any prayers over Initiate level, you can't recall, and you need to atone for your actions. I think the only effect on F1 followers is that they can't recall.