VICKS NYQUIL COLD AND FLU NIGHTTIME RELIEF (ACETAMINOPHEN, DEXTROMETHORPHAN HYDROBROMIDE, AND DOXYLAMINE SUCCINATE) LIQUID [THE PROCTER & GAMBLE MANUFACTURING COMPANY] pain or cough gets worse or lasts more than 7 days fever gets worse or lasts more than 3 days redness or swelling is present new symptoms occur cough comes back or occurs with rash or headache that lasts. These could be signs of a serious condition.