First there is nothing obvious to biopsy, at least according to the ENT, so that isn't on the list. Clicking sound is your tempromandibular (TMJ) joint, lymph nodes can become swollen for tons of reasons only one of which is cancer. If they are swollen you will definitely know it, and painful is something that you won't miss, but means infections not cancer. Blood work will not tell you anything about cancer, but a CBC would tell you if you had an infection. Most are bacterial, but there are also viral as you noted and fungal, which if he tested for one he may not have tested for the others. The ENT to scope you, most of the time passes the scope down through your nose after a little numbing spray, and he gets to see it all from the inside of your nose all the way down to your voice box/larynx. While your fever wasn't off the charts, fever usually ties to infections, not cancer.

So having said all that, I have not answered anything really, but just given you more things to consider. People that have base of tongue cancers frequently feel like things are hard to swallow and/or are hoarse for protracted periods. Neither of which do you mention.

Obviously something isn't right. But you have several things you can pursue. You can get another ENT to look, second opinions never hurt. You could get a blood test and see if your white cell count is up, and that would point you towards an infection, you could go really off the scale and get scanned, like an MRI, and that would look for soft tissue masses. (I think right now this is overkill).

Remember that most of us here are NOT doctors, and that whatever we express to you may be correct or not, but we have seen hundreds of people come through here, and their symptomology is usually about the same when it comes to the dangerous stuff. Were I in your shoes, I would go for the second opinion, have that ENT do some blood work to eliminate an ear/throat etc. infection which could be producing some of this. You didn't mention dentist visits, and a tooth abscess could be a culprit to as far as the lymph nodes are concerned.

Clearly anything that has persisted for this long, and your body is not getting rid of, you need to find the answers for. In general though you have symptoms that are a bit over the map, and some of them are not classic oral cancer symptoms. So I hope that comment relieves any anxiety, if not giving you any firm answers.