Sorry, I couldn't resist, the intense worries about moisturising kinda reminds me of:
But in all seriousness, you really don't need to moisturise every day, especially the back, where skin is usually not dry at all.
I use a lotion on my tattoos only when they get irritated (by clothes or something) or when I lotion whole body after bath, which is no often than once in two weeks or so.