It looks like it could be a meibomian gland inflammation. These are usually not serious unless they become chronic or numerous along the edge of the eyelid, because if they become numerous enough, they CAN cause a form of dry eye, which can be extremely painful and, if not treated, can result in eventual blindness and hyperpigmentation of the eye. The more well-known form of dry eye is keratoconjunctivitis sicca, where the lacrimal gland itself stops working, but dry eye can also be caused by a cessation of operation of the meibomian glands. A quick exam by the vet can tell you exactly what it is and what should be done to either get rid of it or tell you how to live with it so that it doesn't adversely affect your health.
Ghilly
Thank you for the responses!
Masses on the eyelids of dogs are USUALLY benign..it is never a bad idea to have the checked out though. The biggest thing to watch for is that it does not rub on the cornea and cause and ulcer. If you notice your dog squinting or rubbing at the eye, it may need to be removed for those reasons.