Actually you can,..but if you think that it doesn't match your skin tone the definitely take it back,..I can wear all combos of NC & NW 15 & 20, I am a fair olive complexion. A lot of MA's will go a little lighter on concealer,.. Light=brings things forward. If you have dark circles or any shadowing under the eyes they look recessed,.. so in order to bring them forward sometimes a lighter concealer is used. Some people don't like a lighter concealer,. they feel like a "reverse raccoon" though after powdering it that should go away,..these people tend to go a shade darker and more opaque concealer, I personally use a lighter concealer and have not had much success with the second option except in the case of highly pigmented ladies that have severe facial masking.