In the past when conservative treatments like cortisone injections, orthotics, physical therapy and padding failed to achieve relief for conditions like heel pain or painful neuromas...
1) That after removal of the nail there was some damage to the nail matrix (the "root" of the nail). The matrix cells are now arranged such that they will continually grow put abnormal appearing nail due to previous damage.
The solution to this problem would be removing this portion of nail again and applying a chemical to prevent this portion of the nail from ever growing back (a matrixectomy). This is done in office and is almost exactly like the procedure you had done previously.
2)This could be a bacterial or fungal nail infection. If this is the case you would have a nail sample tested to see which organisms are causing the infection and treat with an appropriate topical and/or oral medication.
I hope this answer was helpful,