How do I make poison ivy go away?

Topical. Cold compresses, no scrubbing but gentle hypoallergenic cleansing of the site, topical anti-itch cream (if no open sores, blisters of lesions) and oral antihistamines to keep the itch down. Wear long pants next time!
Best to avoid. If you wash off the juice from poison ivy in 30 minutes you can avoid the rash otherwise corticosteroids topical or if extensive oral steroids are needed.If there is the rash around your eyes seek medical attention immediately as poison ivy in the eye can lead to blindness. Antihistamines may help the itch minimmaly, but do not help the rash. Wash all materials and clothes that touch the poison ivy.