Does neosporin seal up an open cut or burn?

During the first 24-48 hours you may use neosporin. After 24-48 hours you would want to keep the stiches dry. Keeping them moist might not allow the wound to heal, or worse, open the wound back up.

It's also best not to cover the wound (again after 24-48 hours have passed). Unless your going to be in a situation where dirt/debris may enter the wound, like going to the beach. In this case cover the wound only for the time it is at risk of being exposed to dirt.