Heating or cooling certain parts of the tongue can create the illusion of certain tastes. A study published in the journal Nature in 1999 found that, for example, warming the front edge of the tongue (where the chorda tympani nerve is), from a cold temperature, can evoke sweetness. Cooling the same area conjures sourness and/or saltiness. Then, at the back of the tongue (where the glossopharyngeal nerve is), a different set of effects occur. The Yale researchers concluded that thermally sensitive neurons form an everyday part of our sensory code for taste. You will have a runny nose but if it is not that bad,you can still smell.However,if your nose is stuffy enough and it produces lots of discharge(mucus),you will not only having some obstruction to your breathing ,but also will lose the sense of smell.