Regrets, he's had a few.
Madam Pomfrey took Cedric's delivery of one Harry Potter by levitation. "He had some sort of fit, and we've given him calming draught." said Cedric.
Madam Pomfrey cast a few charms on Harry and frowned "There's nothing wrong with him."
"Tongue" said Harry, opening his mouth.
Madam Pomfrey lit her wand and looked in "Oh you've bitten it." she said, and poked her wand at his tongue, healing up the bites. "I'll give you a few vials of calming draught, and some blood replenishing potion to take right now," she said and went off to her office and storeroom, returning with four vials of blue liquid and one vial of dark red liquid.
"Now drink up Potter" she said, handing over the red vial. Harry swigged it with a grimace.
"Now, a good meal and a good nights sleep is what you need." said Madam Pomfrey, pressing the vials into Harry's hand. He slowly put them into a robe pocket with a clink.
"Ahem" said Cedric. "Potter also needs some… health education."
"Health education?" asked Madam Pomfrey.
"Under interrogation by Miss Greengrass and Mr Weasley junior, it became clear that Potter had no idea why any of the suggestive things he might have ever said that set Greengrass off, such that he had his bits hexed, were intentional. Potter thought oral sex was kissing. Ron Weasley gave him some sort of summary in whispers."
"That is highly irregular. I don't think that's an appropriate subject for mixed company." said Madam Pomfrey.
"Potter clearly has a sheltered upbringing. Talk him thorough the booklet. The one you use on broom-closet cases." said Cedric. "He's fifteen, and Greengrass has hexed his bloody bits more than once."
"If a witch cannot hex a foul-mouthed boy she's no better than a muggle," said Madam Pomfrey, "Greengrass the elder has a temper, it's true, but the boy was lewd."
"He honestly didn't know why comments about swallowing even though it tasted bad were suggestive." said Cedric.
"I'm not telling him that," said Madam Pomfrey.
"Accio health education booklet" said Cedric, and he caught the booklet that flew out of the office.
"I'll explain then," said Cedric.
...
A limping, wide-eyed Harry Potter staggered to the near end of the Slytherin table, late for the sorting feast and took a plate, and put some potatoes on it and desultorily bit into one, to blink, swallow and fill his plate hastily with roast beef, peas, cauliflower cheese, gravy, horseradish sauce and gravy and tuck in with gusto, an odd smile on his face. The Syltherins who noticed, shuffled up the table away from him. Potter often resembled a dragon about to do something unpredictable, and strange behaviour boded rather badly.
When the main course platters disappeared and dessert appeared, Harry Potter piled his bowl with a tiny bit of every single dessert, and savoured each one, a beatific smile on his face. He pocketed several humbugs and continued eating dessert.
Professor Dumbledore made a speech, and a pink-robed witch interrupted. Harry looked over at the high table. The witch began to drone on in platitudes, and Harry concentrated on delicious dessert.
As the Slytherins filed down into the dungeons and the common rooms, Harry loitered, finally leaving rubbing his stomach, and staggering downstairs with a smile on his face.
The first-years were being lectured by the latest Slytherin seventh year prefects, when Harry Potter came in, and staggered across the room.
"Potter" said the seventh year male prefect a Priapus Boyle, who was tall and curly-haired.
"Yes?" asked Harry, stopping still.
"Are you drunk?" asked Boyle sharply.
"Should I be?" asked Harry "Just hurt. Madam Pomfrey's already done her bit."
"Come here Potter" said Boyle, and Harry walked over to the high-backed chair Boyle was lounging in. Boyle stood and sniffed "You don't smell drunk." he said and say "Get out of my sight."
"Good evening Boyle" said Harry casually, turned and headed for the fifth year dorms at a slow stagger.
Daphne Greengrass was at a couch on the way with her sister, Tracey Davis, Lily Moon and Pansy.
"Oh, Greengrass..." said Harry "Thank you. You can never know how much you've helped me. Though, don't hex my bits again, or I'll try a particularly nifty organ twisting curse. "
"Is he sick?" asked Tracey.
"Had a fit on the train" said Daphne Greengrass "Possibly side effects of being nearly killed last year with poison."
Harry waved oddly cheerfully and left for the boys dormitory corridor.
Harry entered the fifth year boys dorm, and found the bed with his trunk. He sat heavily and looked around. Zabini was lounging, reading a magazine, Crabbe and Goyle were reading 'What Broomstick' very slowly, and Nott was nervously rearranging books on his study shelf.
"Nott" said Harry firmly. Theo Nott jumped slightly, and turned "Potter?" he asked.
"You're a complete anorak. Which towers are closed off and have no spiral staircase to a top room with windows?" asked Harry.
"You can't expect me to know that" said Theo Nott.
"Nott… I am tired, sore and you are about to be in a lot of pain." said Harry in a monotone.
"Southeast corner, the staircase collapsed" said Nott.
"One with no access except… flying" said Harry.
Nott furrowed his brows.
"One of the small towers" said Harry.
"Any one of the six on the top of the great hall, the decorative tines on the clock tower, or the oddball ones scattered between the Ravenclaw tower and the front entrance tower." said Nott.
"Well done Nott. Sleep well" said Harry.
"Potter" said Blaise Zabini.
"Zabini, I've had a very painful day, and I'm going to go to sleep. In the unlikely event you decide to be assertive, I'm going to demonstrate a very short, easy spell that will have you visiting Madam Pomfrey." said Harry, waving his wand in a circle, swearing, and repeating it, four times, before a shield crackled into life over Harry's bed and he lay back, closed his eyes and fell asleep on the spot.
"You could have taken him" said Nott.
"Because he was exhausted. Tomorrow, he would have hospitalised me." said Zabini.
"Avada Kedavra is two words" said Theo.
"And doesn't work on Harry Potter" said Blaise "But I'm pretty sure neither of us can say that for ourselves. And I don't want to go to Azkaban. St Tropez, not Azkaban."
-==0==-
Harry Potter crawled out of bed, slowly limped to the bathroom past sleeping classmates, and returned, wet, and towel-wrapped, and slowly pulled on underwear, clothes, robes and shoes and walked slowly out of the dormitory, leaning on the wall for support.
He walked slowly across the common-room and left via the secret door, and went to a largely empty great hall, sat and buttered a piece of toast and ate it incredibly slowly, a serene look on his face.
-==0==-
Harry Potter was still eating extremely slowly when the rest of Slytherin house started arriving for breakfast.
"Potter" said Zabini, sitting and pouring coffee from a tiny metal pot into a small cup.
Harry sipped some tea, and sat smiling.
"I still can't understand how you drink that stuff" said Zabini.
Harry sat sipping and nibbling, and eventually, hours later, Professor Snape handed him his timetable. "Try not to have any accidents this year Potter" said Snape. Harry made a point of staring fixedly beyond Professor Snape's head, to avoid eye-contact.