One thing to note about Virginia Creeper is that it thrives in the same growing conditions as does poison ivy. It's not uncommon to find both growing side by side. This past weekend, I observed a Virginia Creeper vine and Poison Ivy vine wrapping around each other and a host tree. So it is possible that you have also come in contact with poison ivy. But from my research (see earlier post on '5 leafed vine' by me), I have found that some people are allergic to Virginia Creeper. Apparently, the sap contains oxalate crystals which is a skin irritant. You may well be one of those who is allergic to Virginia Creeper.

Interesting about your palms as urushiol oil (if this was poison ivy) does not normally cause a reaction there due to thick, tough skin. Palms of hands and soles of feet are generally "immune" due to the thickness of the skin (of course there are always exceptions).

As with any rash, the key is keeping it clean and dry to promote healing.