Few years back my toe nail got crushed accidentally . it was not a major injury but since then my nail has been growing upwards. can i correct the upward growth of the nail ?

Doubtful: Once trauma alters growth of nail from matrix almost always irreversible. Even if remove nail and let it grow back, will grow back same way or worse.

Possible fungus : Often an injury will result in loss of nail with the new nail growing back with fungal involvement. A sampling of the nail should be submitted for fungal culture and if positive it may respond to anti fungal treatment and improve.

Sorry: But crush type injury's that injure the matrix are permanent.

If the matrix: Is damaged. It is damaged and there is nothing to do. To confirm this is the situation, you may want to have the nail removed. If there is thickness send to pathology to analyze for fungus, if fungus present, i would treat. Again, even if there is fungus and you treat if the matrix is damaged from the accident, it will not improve. In case the matrix is not damaged you just optimized your healing.