Tedd can't throw a rock without turning into a girl. Not literally, of course, or that would be method 4.
Someone actually guessed correctly that the mark was on Tedd's head, but I believe that individual primarily likes seeing characters bald, so I'm not entirely certain it wasn't just wishful thinking that they'd have to shave Tedd's head (or at least morph her bald for a bit).
Granted, that's pretty much what they'll have to do to see the shape of the mark, and that could wind up on-panel, so I guess they might get their wish. Huzzah!
I assume those papers on the bulletin board are the same ones from months ago when Grace was hired. That's how bulletin boards work, right? You post something on them, and they stay there forever? I know that's how my bulletin board works.