It doesn't sound particularly worrying. It sounds more like a reaction to being free and making the most of it. We don't put collars on cats that have entropion ops, but if he's tolerating it ok then carry on.
He's very lucky that you've had the op done. It's an extremely painful condition that usually leads to blindness, and he should be fine now.
Sorry about your carpet but really, it was only a matter of time, I'm amazed they remained unscathed for 18 months.
We don't put collars on as a matter of course much at all. Cats hate them so much and most of the time they're fine without them. You do have to see if your cat tries to paw at the eyes a lot I suppose. But at least on the eyes he can't chew at the stitches.