There could be involvement bilaterally, due to the highly lymphatic area, and musculature of the tonsil into the BOT, that can spread to both sides, more so with BOT near midlline. Most tonsils cancers are on the left side, but can be right ipsilateral or bilateral. The tumor is large at T3, and that usually has higher rate of metastases, lymph nodes involvement, but see N0, but could be microscopic, and undetectable now. I wouldn't want to go through treatment twice, I actually did. Your first shot is the best shot.

Is this a trial with Erbitux? It's really not the current recommended first time treatment, outside clinical trials. I would want to add some other chemo, in addition, like Taxotere. Cisplatin was recommended, in addition, but read something from MSKCC with disappointing findings with this combination, but there are other findings noting a higher response rate. Chemo will add 8-22% better response to treatment, depending on type.

I had bilateral IMRT 70 Gy with T1N2bM0 disease. They might do lesser to the left side, and cervical neck.

Good luck.