Well, it's different, that's for sure

There was no denying it. His cock had grown to a ridiculous degree, and he wasn't even hard yet! He had measured himself once before, a few months ago, and had felt relieved that he was actually pretty big at seven inches and a half long, compared to the 5.5-inch average. Now? It felt like almost double that much, and its girth was likewise almost unrecognizable. Hell, even his foreskin had grown back from circumcision, covering the head of his penis in a thick, veiny layer of skin. While still within human limits, he was easily pornstar material with this thing between his legs.

"U-Uh... R-Recovery Girl...?" His voice trembled with pure embarrassment, but he just had to mention this. The change very clearly supported her side effect theory, and she could possibly be the only one around he could trust with his bodily wellbeing.

"What is it? Sorry, I don't have any other material. Maybe try using your imagination, I hear Midnight's pretty popular-" She started, but he had to interrupt her mid-sentence.

"I-It's not that! Something's wrong!"

"Oh?" He could hear her footsteps approaching the bathroom.

"Um... the size, it's... err... m-my..." How would he even just... say something like this? Do people just go 'yeah my dick just grew like seven inches' all casually like that???

"Boy, just spit it out. For the sake of your health, I need to know what just happened."

"Hrm... my p-penis is almost twice as large a-and, um, g-girthy? As it was yesterday." He just blurted most of that out to get it over with without overthinking. "E-Even my... f-foreskin's back, and... it has a strong and weird, um, smell, coming from it?" There were few things he wanted more than throwing himself out the window at that moment.

"My, my, that is quite the interesting side effect. Cute face, strong and athletic, smart, and now massively endowed. I bet you'll be popular with the girls." The nurse teased, maybe in an attempt to make him feel more relaxed. If anything, it only ever made him more nervous to come out of that room - now he'd be self-conscious about the massive bulge his member would leave on anything he wore.

"I need you to give me that sample regardless, just so I can analyze your DNA, see what went wrong with your Quirk. If you feel like you need a bigger container, just ask and I'll bring you one. For now, I'll sit next to the door in case you find anything else, alright? If anything feels weird, bigger, smaller, whatever it is, just tell me."

Well... no escape from this situation now. The quicker he dealt with this, the quicker he could go back to being a hero student. Still, it took him a while to get used to his new size. The amount of lube he had to push out to coat his entire cock in a nice and slick amount was far more than he was used to, and made him feel wasteful; the motions were completely different, as now he had to follow a larger curve and somehow try to pleasure about thirteen inches of dick with his two small hands that didn't even wrap around the thing entirely. Having so much skin at the top only made it even weirder. At least it didn't grow that much from soft to hard; he was a shower for sure.

That aside? If he had to describe his experience, he'd probably have to admit it was his best fap ever. That fat, massive member felt every bit as sensitive as it used to, except spread over a much larger area. When he managed to slide back the foreskin at the tip, his frenulum and the space between the head and shaft both felt almost electrifyingly good, and quickly became the focus of his ministrations. His balls, which he noted to the nurse were likewise all bloated and much bigger than they used to, felt stuffed with thick, virile spunk, and each stroke of his shaft saw his tip effectively drooling precum out. He probably didn't need lube to begin with, not anymore.

By the time he was done in that bathroom, about half an hour later, he had come out with two beer mugs filled to the brim with his cum, which he had luckily asked for as he was getting closer to the edge. "S-Sorry for dirtying so much stuff, I... I think it kinda came out a second time while I still wasn't done w-with the first one..."

"No worries, boy, just leave the mugs on my desk and go to class already. Your classmates must be wondering how long these tests are supposed to take."

Oh, right, class!

A green flash was all that was left of him as he sped down the hallways. The nurse facepalmed; he forgot about his promise to not injure himself so soon already.