From what you have written, it seems like you had a high-grade dysplasia or "Carcinoma In Situ (CIS)" but seems like it has progressed with some invasion of the surrounding tissues.

Technically it is TisN0M0 (Stage 0) and you have been lucky to catch it very early before it could turn invasive and tumorous. Just keep a close watch and stick to the follow up schedule (Next month and then once in three months?). I would suggest to get a PET scan after 6 months just to be sure about Lymph nodes.

You missed by a whisker so take good care.

Father; 67 yrs; RIP: 2012/05/26

TX:SCC pT2N1M0G2;Glossectomy+SND+CCRT(59.3Gy+6xCis.)[2009]
TX:Nodal Mets; 3xDCF[2011/05/05]
TX: RND + PMMC Flap[2011/07/11]
DX:SCC PNI+ECE
TX:Re-RT 60Gy[2011/09/21]
TX:Gefitinib 250mg[2011/12/18]