Singing over a cold:
There are times when you can sing with a cold and times when you absolutely must rest your voice. When the occasional cold comes on, sometimes you can rely on breath support and body awareness to get through rehearsals and concerts without exacerbating fatigue or doing permanent damage.
You can usually sing over a cold if you have nasal congestion but no throat symptoms. Your tone may be a bit nasal, but in general, you can sing over or through congestion. The first line of treatment for your singing voice is moisture. Drinking a lot of water will keep your throat and nasal mucus thin. Inhaling steam seems to be helpful for the same reason. Cough drops can keep you from coughing to the point of hoarseness. However, the sugar and menthol in them can make you feel dry. Caffeine-free herbal teas can be soothing and add moisture back to your system. Caffeine, alcohol, and smoking should be avoided because they all have a drying effect on your voice and body.
Happy Singing!!