I wouldn't necessarily go as far as saying that Paul "made it all up." I'm not sure there is enough evidence for that claim. I'm just saying that I think Paul's claims aren't enough to overcome the high burden of proof required to make his testimony good evidence.
It's possible that Paul was simply mistaken or poorly communicating or had his understanding of the event distorted by some other outside pressure, or the surviving copies we have of Paul are different from what he actually wrote, etc. There are a number of alternative explanations for why Paul's writings say what they do and intentional deceit is only one of several options.
I wouldn't make a hard claim on any of those. I just think that Paul is a biased source and much of what he claims cannot be backed up, which makes him unreliable.