I used to lick the cheese dust off doritos and put them back in the bag when I was a little kid
No way you did that. That is gross!
It's no secret that people's past has a major influence on who they become
As long as you do not do that still, I think it is fine. You should not lick food that other people are going to put in their mouth.
But it was so good and I was just a kid.
Yeah, kids really do the strangest things so that's all forgivable. I hope if you do every see yourself doing that again, you can tell others so they don't have to eat your spit from your bag of chips!