I do not think this is a zeref mark. Jellal has always had this mark so it must not be Zeref related because Jellal didn't meet "zeref" (or should I say Ultear...) until later. Mystogan must also have it because he is the Edolas Jellal.
I'm pretty sure that he always had the mark around his eye, Jellal that is, it had nothing to do with zeref, watch the first couple of episodes in the Tower of Heaven arc,. He had the tattoo from the very youngest age they show him, it might be a birthmark, cos i think i remember mystogan having it as a baby.
