Board Thread:Theories and Speculation/@comment-1872728-20200725151448/@comment-32685487-20200730181341

The Curse Mark was not on Kabuto, nor was it on Orochimaru after the 4th War. So I'm sure the Curse Mark was created after Orochimaru visited Ryuchi Cave. Kimimaro had Jugo go to Oro to have Oro help him control his urges and power so I think that may be what Jugo's Curse Mark is, an attempt at controlling his urges and power.