once you receive nerve injury
then its irreversible because the neurons are the only cells in the body which donot regenerates however you concern about the squint
is that can be corrected at any time when ever you want. its a surgical procedure which involves the strengthening of you lag(weak) muscle of the eye and subsequently its shortening thus keep the eyeball the at its actual position. therefore you should consult an ophthalmic surgeon for your problem and you get solution for it.