Sorry to hear that you are dealing with recurrent sores in your throat and that you are worried you may have a cancer. Before I give you my thoughts on what might be going on, I would recommend going to an Ear Nose and Throat specialist (aka otolaryngologist
, or ENT physician). This is because despite what I may be able to tell you, I am not able to examine you, or even take a thorough history, both of which are fundamental to the diagnostic process. With that being said, it sounds like you are getting a recurrent blister somewhere in your throat which is much more likely an inflammatory process (such as from HSV which you already know that you have). In general head and neck cancers do not come and go. Typically they will present as a slowly enlarging mass or a pain that won't go away. No as something that comes and goes, and comes back a few months later. The two biggest risk factors for developing a head and neck cancer are smoking and excessive alcohol intake. As I'm sure you are aware, there are medications that you can take for herpes outbreaks, however unfortunately there is no 'cure' for herpes. It is not uncommon to have 'fare-ups' of herpes with immunosuppression (such as taking steroids) or during times of stress. Again, please schedule an appointment with an ENT physician. I wish you all the best and hope that this in part answers your questions.