Possible Clues:

• Upset at American fools, giving bad marks
• Mercian king who built dyke
• It's turning heads to get more attention than academic marks
• At AGM, it's sadly evidence of shame
• Marks in game got by mother during brief go
• Letter from Greece about tyrannical leader that's appreciated as evidence of suffering
• Part of flower that oddly makes impression on Francis
• Saint, disturbed at Magi revealing marks on his body?
• Wound
• Signs of suffering as Athenian character volunteers to accept budget, finally