What can I do to help my allergy hives when no OTC medicine or cream seems to help?

See an allergist. The best treatment for hives is to avoid whatever is causing them; an allergist can help with the identification. In the majority of cases in which no cause can be identified, prescription medications can be vastly more effective than what is available over the counter.
See an allergist. Otc medications are very helpful for a lot of allergies nowadays, but if your symptoms do not respond to them, it's time to see a specialist who can prescribe something stronger. If you know the cause of your hives, you can try to avoid the trigger; if you don't, an allergist can help you try to find your triggers and teach you more about avoidance.