Overtime blocked FG

[Theisey]

Unfortunately, your answer will be state dependent. I can't give you a specific answer.

Here in NY, we use the states version of OT. Any time Team-B gains possession of the ball, team-A's series if over and team-B starts their series.

So in the case of a blocked FG, until team-B gets possession, it's still live for team-A while it's behind the NZ. If it goes beyond, then normal scrimmage kick rules apply for team-A. Regardless once team-B gets control, the down is over.