Tonsil veins showing red & black. What does this mean?

Tonsil vessels. Many of the soft tissues that line the mouth and throat have visible blood vessels. This is quite normal. Sometimes those vessels are red or purple. Black would not be a typical color for a vessel although depending on your light source (flashlight), a purple vessel could look black. Without actually examining your tonsils directly, it would be difficult to say what it is. Have an ENT dr look.