Hi there, I ve had what looks like some kind of ulcer or canker sore or something on my tongue for a couple of days, I was just looking in the mirror to see what it looks like (it has a yellow bit in the middle of the sore) and I noticed that like half my tongue is yellow, and I can scrape at the yellow stuff, and it also has all these red dots at the front of my tongue. And my throat has been sore when I swallow but only slightly. What is this yellow stuff please? Could it just be plaque? Or do I have some kind of infection? Thank you