Hey Suresh

Most of the times your marks wont be deducted or reduced in retotalling or re evaluation (if you have actually written good answers and you deserve how much you have got or more). If you have written totally incorrect or off the point ansers and the teacher who is rechecking your marks is not the "good" kind you will lose out on those marks (however it rarely happens). Also, even if you lose out on a few marks your life will still go on. Most of the colleges in India take admission via entrance tests so your 12th marks wont really matter much. All the best.