Ah mate, I'm sorry to hear you're in pain. The end is nigh and you're doing so well. Cold things help massively. I was drinking iced frappucinos in October, just to get relief and calories. Gargling warm water helps too, it also refreshes the mouth. Another calorie booster is making a sweet coffee with cream instead of milk, or (if you can taste chocolate), melt a bar of chocolate into cream. You can drink it warm or cold.