To answer your questions:
1) The presentation of lymph nodes after mononucleosis can vary. Although atypical, it may be possible for lymph nodes to present in that fashion after mono.
2) It would depend on what the cause is. A biopsy is the only sure way to exclude cancer.
3) A normal blood count would make cancer less likely. However, as mentioned above, a biopsy is the only sure way to tell.
This option can be discussed with your personal physician, or in conjunction with an ENT physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
kevinmd_b