The most common symptoms of acute mononucleosis include: 1. Swollen tonsils 2. Sore throat 3. Enlarged and tender lymph nodes 4. Fatigue 5. Fever 6. Rash 7. Enlarged liver and spleen You can have an acute mono infection and not know it because symptoms are very mild or don’t exist. Symptoms can be more severe causing airway blockage and extended illness. After the acute infection has resolved, fatigue and enlarged tonsils can persist for weeks and even months. Now that it’s time to return to sch