The band applies in 2nd and 4th. If the band moved while you had the servo pin out and you re-installed it and missed the band lug, you would not have 2nd or 4th gear.
You may be able to remove the servo and get the band positioned correctly with a screwdriver or punch. You may have to drop the pan and get access to the band to help align it.
Hopefully you didn't hurt the band or any frictions (3-4 clutches) while driving it with it improperly assembled.