It is most likely far too late to correct the problem
Any correction, if possible, would only be temporary.
Remember the memory (of a panel in that condition).
Can you hand assemble the lead-in-hole components?
How will the board be connected to its assembly?
Who built the board?
Was the laminate purchased to a particular specification?....there is
normally a warp and twist requirement.
Was the board purchased to a paricular specification that called out warp and
twist?
Good luck.