Dear Sushant, don't worry your form won't get rejected.  You can change the marks when the correction window opens. The authority provides a correction window facility which can be used to correct any errors inadvertently made by the candidates at the time of filling the application form of NEET PG. The correction window facility will be tentatively in the last week of December 2019. Only those candidates who will submit the application form on or before the last date will be issued NEET PG admit card from December 28, 2019.

All the best

Hope this helps