I've got a very painful herpes sore on my tongue. Is there any o.T.C. Treatment that may help?

Orabase. Otc orabase by colgate will create a thin film over the sore and provide temporary pain relief topically. It is one of the best otc treatments as it will stick to the sore for a longer period of time thanother otc meds. Also see a doctor about rx for meds to take to limit herpes sores in the future.
Antiviral. There are probably many otc meds. But an exam by a physician is highly encouraged.