Head counts at a decade's worth of proms? (11), 8 letters
Completed some courses?, 9 letters
Supped at six, perhaps, 9 letters
Took a night course?, 9 letters
Took evening courses?, 9 letters
Topped some chips at the pool party, say, 6 letters
Accepted bad treatment, 7 letters
Accepted guilt humbly, 7 letters
Suffered an embarrassing defeat, 7 letters
Swallowed humble pie, 7 letters