sap burn?
 

i was riding a pretty tight single track the other day, and somewhere along the way i got tree sap all over the inside of my elbow. no bugs or stix, just sap. got back to camp, used a tiny bit of gas to wipe it off. now i have a rash, and one large open sore that looks like a botfly larvae! i live in montana so it obviously not a botfly, but has anyone else had this happen before? ive used gas to clean skin hundreds of times, never gotten a rash from it before though..

With the degrading quality of US gasoline over the last few years, I wouldn't be surprised if it did have botfly larvae in it.

I know Leafy Spurge sap will cause a good rash. You didn't get into any along the ride did you?

Another sap culprit could be the Tree of Heaven, but I don't think they have invaded west of Missouri yet.

no idea, im pretty sure it was pine or fir, wast paying much attention to the scenery whizzing by :)
it started as a needle gun type wound, one in the middle, and four or five little ones around it, then it turned into a single big sore.

This may not be the culprit it may just be an allergic reaction to a pine needle puncture. I have seen it happen to someone before. Thought I would share another possibility though.

There is a plant called giant hog weed which is on the noxious plant list. Its sap burns the skin and its stems have sharp needle like hairs. They grow fast and huge and have leaves much like a skunk cabbage plant but much larger. Usually found in dense areas though and they like moist damp soil. In my line of work, we are often called out to nuke this stuff. Introduced from Europe, it is found in many places across the U.S. Link below

http://dnr.metrokc.gov/wlr/lands/weeds/hogweed.htm

Roscoe