Taylor the Dinosaur's poem is just one line long, yet it holds a whole argument. The speaker begins with a familiar idea: to forgive someone is to forget what they did. Then the question at the end quietly knocks that idea down. If a wound has left a scar, how could anyone forget it? The scar is right there, on the body, a permanent reminder.
The speaker seems to be caught between wanting to forgive and being unable to let the memory go. The title, "Cannot Forget," makes that struggle plain. The poem doesn't say whether forgiveness is possible, only that it can't mean erasing the past.
The mood is quiet, tired, and a little sore. There's no anger shouted here, just a heavy honesty. The scar suggests the hurt has healed on the surface but still shows, and the speaker can't pretend otherwise.