hello treatment of squint (exercise or surgery) depends on type and amount of squint being squint specialist , i need to see photo of ur eyes so that i may guide you better

At the age of 12 years you were operated in squinting eye which was having very less vision and  before surgery there should have Pleoptic treatment ( at age of 10 -12 years or less) to equalize vision in both eyes. That time wrong procedures were adopted. First pleoptic treatment for the improvement of vision in the affected eye should have been done in a higher centre or where ever Pleoptic or orthoptics department is available.When vision in both eyes becomes almost equal, then squint surgery should have been done. Pleoptic exercise is effective only up to 10 to 12 years of age. When amblyopic eye is operated without improvement of vision it regains the anatomical position ( divergent squint ) in next 5 to 10 years. Your  eye has again become divergent Squint if you undergo repeat surgery,  there may be slight improvement but the eyeball will regain the position of divergent squint in 5 years because eye remains in straight position only when there is normal vision in the affected eye.

First of all  we need to know how much  vision is there in squinting eye . So a full assessment is mandatory Yes one can undergo a resurgery but one has to again keep in mind the chance of recurrence Also if you know the details of the previous surgery it would be really helpful to the surgeon