Simon looked ... different at the Kids' Choice Awards 2022 as he sauntered in ... actually, remarkably different -- in a good way.

Simon posed with other judges from "America's Got Talent" ... showing off his new appearance since he has stopped getting Botox treatments.

As for why ... it's the age-old truism -- emphasis on age -- that guys generally look worse when they get shot up with fillers. As Simon put it, he looked "like something out a horror film".

He went even further, confessing his son, Eric, was in hysterics over his filled-in face and that's when he realized enough was enough.

"There was a stage where I might have gone a bit too far. I saw a picture of me from ‘before' the other day, and didn’t recognize it as me first of all" ... he said.

Now, the "American Idol" judge says it's all about having clear skin ... "I probably did have a little too much Botox a couple of years ago, because everyone on TV has it. Now I have facials, but nothing too extravagant at the moment."