Aroma is one of the most valuable tools in beer evaluation. You should smell your beer frequently while performing sensory testing, and if you haven't gotten foam up your nose yet, you're not doing it right. Get in there and enjoy it!
Because the olfactory sensors are overloaded very quickly, you'll need to clear your nose after you smell the beer, and repeat the process several times. The best way to clear your nose after smelling the beer is to sniff your own sleeve, which might sound kind of odd, but is very effective.