White stuff on my tonsils? What is it?

I've been having pain for 2 days now, I went to my doctor yesterday. He did the usual throat swab, and nothing was white then. I woke up, took my penicillin like I have to. I got home and decided to take a look at my tonsils, and theres white blotches on my right tonsil. I feel like puking looking at them. Yuck!