Nope. Just for that measure. Bar line: back to the present key
signature. If you're changing back to the original(previous measure) key
orientation within the measure, you've got to "naturalize" (neutralize?)
that accidental within the measure. Any alterations longer than a measure
must be changed at the next measure or a new key signature must be
indicated. In a related way, jazz tunes often temporarily change keys
within the piece but they rarely indicate the key change from the key
signature, that's more common in classical.
David