Boil some water (the amount doesn't matter) and pour it into a bowl. Put your face over the bowl and breath in the steam with your nose. This should help a little. Once the water cools enough to touch, dip a napkin or a dish towel into the water and put the corner of it into your nostril. Leave it in for however you feel is necessary. This will help relieve some pressure but you should probably follow up with medicine or nasal spray.