I have a painful red veiny patch on the middle left side of my palate for about 10 days now. I don't remember really how it appeared. I vaguely remember burning my palate from that side with food, but not so sure about that either. I use corsodyl toothpaste and mouthwash, it hasn't improved really. Today, I started using igloo gel rapid relief for mouth ulcers. It just numbs the irritation by creating a filter on top, so it stops the irritation with food. When should I start getting worried about mouth cancer? Thank you...