Personally, I'd say don't panic you should be okay. It's unlikely you took the 4 full grams of paracetamol, and even if you did that's not a fatal amount. Back in the day when I had a big dhc habit, I lost my supply and brought some Paramol. Normally I'd try and extract the good stuff, but that wasn't possible where I was, so I very stupidly took 9 of the things. I didn't have any symptoms, but I got the LFT and blood tests at hospital cause I was worried as fuck, and my liver turned out to be perfectly healthy.