Interesting update and by bringing in the parseltongue ability, I am assuming that you read the other story where he removed the dark mark with snake-speak. I look forward to your update.
Author's response
As always, thank you for reading and reviewing, and for your encouragement. I haven't read the fic that used Harry's innate Parselspeak ability to remove a dark mark - good thing. My method is somewhat different, but will prove to be effective. To say more would be a serious spoiler . . .