when you took the strings off, the truss was most likley adjusted to counteract the string tension, the string tension will put a slight bow in the neck, the truss adjustment counteracts this and straightens it out.
So when you take the strings off and do not relax the truss rod to a neutral position, the truss rod is now acting on neck but no longer has the string tension pulling it, so therefore the still engaged rod is stressing it and putting the back bow into the neck as that is the direction it bends the neck to counteract the string pull
How permanent this is would be is unknown. I would suggest loosening the rod and allowing the neck to sit "free" to see if it has an inclination to straighten out by itself. Or try installing the strings not tuned up all the way, and do not tension the rod and see if they act like slow acting come alongs that help straighten it to a more neutral position.
|