I have eczema on one eyelid, been treating with 1% cortisone cream for 8 mos. My eyelid is drooping, is this caused by cortisone, and will it resolve?

Possible. Use of corticosteroid ophthalmic drops have rarely been reported to cause ptosis. Corticosteroids can cause muscle weakness(corticosteroid myopathy). The thinest skin in the body is in the eyelid. It is conceivable that prolonged use could cause weakness of the levator palpebrae superioris muscle that raises the eyelid.
Topical steroids. Usually we recommend not using topical steroid preparations (like cortisone) for more than 2 weeks at a time, because the steroid medication can cause thinning of the skin structure and can even cause ongoing irritation which mimics the original "rash". The skin around the eyes is the thinnest/most delicate in the body, & the drooping may indeed be from the steroid. Stop using it and see derm.