@Bekkasan! :hugs: Thanks for the feedback on Christopher!
So you've gone over to the 'dark side' with CC skins, eh? :D I don't have any non-default skins in my game atm, but I created a new TS3 folder with only a fraction of my Store content installed because I am helping a modder test a mod for the Store Canning Station. But I often end up taking them out anyway! I think I only have one ND in my 'normal' TS3 folder.
You select them the same way you change any sims skin color; they usually show up in the skin panel with some kind of special color or writing on them but sometimes they are just purple or black or some other funky color. They can be difficult to tell apart sometimes, especially if you have several of them.
I found some CC freckles that are really nice to use in place of the freckled skins. I am just really picky about which skins I like and which ones I don't! Just for reference, the eyes in that pic are from MTS, Escand Oh My Eyes. I have some other contacts that I like a lot but those are my default replacement eyes. I also - for now - switched to Brntwaffles Fresh Blue as my default skin (not sure if that's the one you have or not). That's what I used for Christopher.