So I found a screw embedded in my tire.....it's really stuck in there....is it possible it's affecting my tire and making air leak out, or is it ok since it's stuck in there?

get it patched now, its like 5$ at any tire or repair type place

How long does the patch last?

The patch done correctly should not wear out? You can patch it and forget it. :-) *Caveat being your in the Sahara out there make sure they just don't do a plug get them to patch it from the i...