I would suggest if you got/ get airborne in a configuration where the CofG is beyond the aft limit, then you do not make any large/ sudden inputs on any controls/ change power gently /dont alter flaps/gear. The aircraft will be close to being unstable longitudinally, and could diverge in pitch, nose-up/down.
Fly very gently around and get it on the ground
Lateral/directional stability will also be affected, so it must be flown carefully,as balanced as possible and as smoothly as possible. Most a/c will be able to cope with the CofG behind the aft limit; they will have been tested , and normal limits will be inside those boundaries.
Then, back on the ground, go back and do the calcs. again!!!