Is tylenol ibuprofen or acetaminophen

I like your story. Your caveat about discontinuities at the top was way too understated, they were jarring, but I get it. I've been there myself, but please remember to come back and clean up later, you're going to throw a lot of people off.
OK, big problem: Never, ever, ever take Advil and Tylenol together! Ever! Tylenol is Acetaminophen, it's a blood thinner. Advil is Ibuprofen, it's an anti-inflammatory that will also irritate your stomach lining. So between the two, you'll end up with a bleeding ulcer. I think the standard recommendation is to separate them by at least twelve hours, though I just stick to one. So unless you're TRYING to mess Hayley up even worse than she already is (bruised, battered, hung over), PLEASE stick to one or the other.
PS: Yes, this is a pet peeve. Yes, I've personally had a problem with both drugs. Google it if you don't believe me.

It is tylenol. If you want real pain relief, take Advil.

I very much enjoyed the story, a full 5 stars.
Unlike some, I've no problems with April being a little peeved at the beginning, we can all lose sight of someone's worth occasionally. If she was an ingrate, or it was Charles's grooming, is an imponderable mystery within the story.
Because you didn't make some things clear, or read your own story, or because I'm a pedant.
This was set during the Covid, yet a health centre didn't revert to the default that everything was covid and had a doctor that was free to be dispatched to June within minutes?
In appraising Dr. Satapathy, she was no older than Paul's 39 years, later on Paul is in his early 40s?
Cafés, restaurants sports centres (Paul's dojo) were all open and there is no mention of masks anywhere.
April wearing raunchy underwear for Paul. To be fair, you didn't say Paul's new job was Monday to Thursday, but you did say it was four days per week. I thought Aprils early show on Thursday morning was to prime Paul for the long weekend.
April feeding Paul sushi. No mention made of what had wasabi on it or what was dipped into soy sauce and how Paul told April his preferences. Well, I told you I was a pedant.
The drugs for June were mentioned and Tylenol was included. Tylenol is acetaminophen, which is also used in many cough medicines. Later on in the story, the alternative name for acetaminophen is used, which is paracetamol.

Loved the story - but just as an aside, aspirin actually prevents liver damage. Acetameniphen (Tylenol) is what is traditionally known as dangerous for the liver, and non-aspirin NSAIDs such as ibuprofen have recently been linked to stroke/heart attack risk increase. lol I know this has nothing to do with erotica, and your story is fantastic - but if it were me writing this? (and I do write a ton - I'm actually a professional author), I would have had Jack (the athlete) share his prescription pain killers with his victim, since he's most likely on them (athletes are always getting hurt) and since opiate prescriptions, added Tylenol not withstanding, are the only things that don't increase the risk of liver damage and heart attack/stroke. Plus... let's be honest. They're also the only medications that actually work. And also - it's the very least Jack owes him. ;)

Never take Tylenol after drinking. The risk of fulminant and complete liver failure is not insignificant and the results are catastrophic.

I hope I'm wrong but I see the foreshadowing of the magic reconciliation impulse center brain tumor with the tylenol headaches