My platelet distribution width is 16.4 is this dangerous and how can i help to correct it my vit b12 is also 671 is there a connection between the two?

Stop worrying: Platelet distribution width is of no concern at all if you are otherwise healthy. If this B12 is in picograms/ml then this is likely within the reference range; it's worrisome only if it's low and a high value in someone who's otherwise healthy isn't anything to worry about. Ranges are actually set so that several percent of normal folks fall outside.