My 7-year-old son has started getting sudden brown spots on his skin. The first one appeared behind his neck, then another near his collarbone, and the third one on his ribs. The spots arent itchy or painful, and theyre just brown, not any other color like blue. Im concerned and not sure whats causing them. Can you guide me on what this could be?

That could be P versicolr infection or vitamin deficiency, visit Dermatologist for evaluation and appropriate treatment.no need to worry.