This is unlikely unless your nostrils were made to be smaller with suture techniques during Rhinoplasty. If this were the case, your nose picking could have dislodged or broken some key sutures that were keeping your nose a certain shape. Also if your nostrils were made smaller from the surgery, your nose picking could have stretched out the reshapened nostrils and made them smaller. Making your nostrils bigger is actually less of a concern than if you were to tell me that your nose is smaller after picking your nose. Contractures can happen that can make your nostril smaller and the correction of this is much more involved requiring grafts to enlarge the nostril and sometimes the need for multiple revisions to enlarge the nostril.
Dr Young is located in Bellevue near Seattle, Washington