Is Mononucleosis A Recurrent Disease?

my daughter is 21 years old. She has had mononucleosis before. Can she get it again? She is a very busy college student with little down time. She had an infection in her back tooth that was below the tooth and kept coming back. She was getting a bad taste in her moth thinking it was from the tooth. The surgeon took the tooth out a month ago due to the repeated infection under the tooth. He explained it was creating a seal under the tooth and wood just keep coming back. my daughter was taking different types of penicillin each time she had a flair up over the last year and 1/2. she now is still having that bad taste in her mouth and thinks it could be her tonsils are very large ? she also wakes up some days not feeling rested. She has had some weight gain , sweats easily, cold feet, ill feeling, dry scalp, abdominal pain -has irritable bowel - Hypothyroidism?