Yes they do. Not me though as I don't have time. My friends all do it and have admitted to it. They spend a rather long amount of time editing each picture because it 'looks so much more amazing afterwards'. Tbh, why be a fraud of yourself because it's not only wasting personal time, but other people's time. MY advice, just be yourself.
I love editing photos, I don't do it because I find myself ugly but I enjoy photography a lot and I like how different you can make a photo look by using different settings, filters, etc.
I don't post a lot of photos on Facebook though, but if I do they're most likely edited. There's a lot of unedited photos that I'm tagged on and I don't mind them at all, I don't have anything to hide.
I know a lot used to do some editing back when we were in the teen years.. Now there are a few who use the Instagram filters, but nothing more obvious than that.
I can't bring myself to give a ****. I avoid cameras like the plague, so have very few photos, and I am selective enough with my FB friends that most will have seen me bleary-eyed and haggard at some point anyway..
In pictures I like I have occasionally used the 'autocorrect' tool which adjusts brightness and contrast so you can see the picture best (it is not a blemish covering or an enhancer in any way, just makes you see things better in the picture, less grey and such). I think a lot of people abuse instagram or other editing tools - but I don't like to do that.