Surgery usually cures the haemorrhoids but the long term success of surgery depends upon how well you have been able to change your daily bowel habits to avoid constipation
About 5 out of 100 cases get their haemorrhoids back after the surgery because of poor habits.
Take plenty of water,take large amount of fibre and keep constipation away.
You may take some laxatives for the time being and consult your surgeon again.
As far as fruity smell in bowel movement is concerned it could be sign of diabetes
results in fruity smell in urine and bowel movements.