Yes, I did an assignment on this. Get it checked by the doctor. You might be in risk of Testicular Cancer.
I have a small bump on my left testicle its like a big pimple before it was red now its blue inside, i am not sure what it is but if its not a lump inside ur ball its probably not cancer, it just stays there it's been like a month now, I'm a little paranoid, when i try to pop it once or twice puss came out but nothing anymore