What will happen if you eat a banana that already has spots? Bad or Good?

Ripe bananas, particularly those with some spots, contain more soluble fiber as compared to their greener counterparts.
Soluble fiber can help to regulate digestion and prevent constipation.
It also aids in maintaining stable blood sugar levels and provides a prolonged feeling of fullness, which is beneficial for weight management.
To sum up, rather than judging bananas by their cover—or peel, in this case—the development of spots on bananas should be seen as an enhancement of the fruit’s health benefits.