One tonsil is huge and covered in pus, the other is fine. Tested negative for both strep and mono. Any suggestions?

Tonsilar abscess. Please see an ear, nose and throat specialist. If you have pus on your tonsil that is not getting better may need to have it drained or removed as it may be an abscess. Antibiotics can help but sometimes the infection can keep coming back. If you have difficulty breathing or swallowing, go to the ED right away.