Welcome back, Holly!
So, as a potential tourist who has never been to Scotland before and wants to see awesome sights without standing in tourist lines - should we elect to spend 2-3 days in which = Glasgow or Edinburgh?
First of all congrats on your new tattoo! What did you end up getting?
Second, friction can affect a tattoo overtime. That's why things like finger, palm, and sometimes ankle can feet tattoo are prone to fading much more quickly. There will be a lot of things that can cause your tattoo to fade, and no matter what it will fade with age. I don't think the arm sleeve would hurt it any more, but I wouldn't obsess with it too much. Just take care of it, keep it and your self hydrated and moisturized, and remember you can always get it touched up in the years to come!