You'll never look dumb pulling out reference material if you do it correctly. If anybody asks, say you're confirming something. This can actually instill confidence in your patients, and shows them that you know when to ask for help. That being said, you should have basic knowledge that the reference material supplements, not replaces.
My ID lanyard that I use for all of my jobs (ICU and ER nursing) has a Fahrenheit to Celsius reference card, as well as a reference card for the pressors that we use (mixing instructions, starting doses, titration protocols, etc). I also have a card on there for push-pressor doses (neo and epi). Easy to quickly look at for reference when needed. There's also some other stuff on there that's more operations related (for example, how to reprint lab labels, because apparently that and correctly buttoning the sleeves on hospital gowns are the most difficult things about nursing). When I'm doing ambulance ride time for paramedic school, I carry my protocol book (pocket sized) and my phone with me. Nothing else. I have made cheat sheets for other things in the past (weight conversions, etc).
Moral of the story is, yes I use cheat sheets for some things and have no problem with people using them, but if you're using them they should be as a reference, not as a complete guide.