Is lagophthalmos after ptosis surgery (resulted with overcorrection) curable? Or are we condemned to that?

Not sure if enought, but in my experience the Fasanella Servat procedure (probably you have received this) adapts and settles with time to the right correction; if frontal suspension technique was used then it will not correct, and you'll need a touch up to release the tension of the slings.

Your question is a very good one. The answer depends in large part on what type of correction you had, as there are several approaches. Revision surgery for ptosis under/overcorrection is not that uncommon. Whether or not it can or should be done earlier or later is best answered by your surgeon. However, eventually you should end up where you need to be. BRK