Couple of days ago I had a disagreement with my roommate and to make a long story short she through my flash drive out in our back yard in the rain. I haven't found it yet and it rained for two days straight. When I find it do you think the rain will have ruined it or will I be able to get my data off it?

The question is whether something will have been shorted out. Since USB Flash drives are not powered unless they are inserted into a computer, there is no voltage to damage the device (unless it got zapped by static electricity or by a lightning bolt).

Sometimes you can dry out electronic gear and it will work fine. I think there is a fairly high probability that it will be fine -- but you'll have to make absolutely sure that it's very dry before you insert it into a computer. I would probably put it in a small, fairly warm space (say a box with a light bulb in it, or something similar) for at least a day.

I accidentally washed my fav jum drive and I let it sit for a day and it worked fine so you shouldn't have any problem

Rinse tjouroghly.
Dry.
Place in a ziplock bag full of rice for a day.