Healthy 21 mo old noticed for 2 dys she has puffiness under both of eyes under lash line. Has not been sick or noticeable congestion. .. Dr or wait?

Depends. If the puffiness is red and tender to touch, you should take her in. If it's just puffy and she doesn't have any other symptoms I would just monitor for fevers or other signs of illness.
Try antihistamine. It may be allergy related. Try Claritin (loratadine) over the counter daily. If not better in a week or so, check with doctor. If any vision changes or discharge from the eyes, check with the doctor sooner.