The correction window of NTA UG NEET application form will open from 14/01/2019 to 31/01/2019. You can make necessary corrections at that time. Last year CBSE conducted NEET and they allowed corrections for GENDER, CATEGORY, IDENTITY and even STATE CODE OF ELIGIBILITY. So you may expect permission from NTA to correct the state code of eligibility. As of now there is no notification of any sorts from NTA regarding what you may correct but DEFINITELY THEY WILL NOT ALLOW SOMETHING THAT MIGHT AFFECT THE CANDIDATE'S MERIT

To be on a safe side you may send an email to the NTA officials and state your problem. Then you will have more clarification. Please do not panick and focus on yoir studies. All is not lost. Wait for Jan 14 . 

Best of Luck

Hi there. 

The correction window will be open from January 19 to January 31, 2019. During the correction window candidates won't be able to change their category, gender, nationality, State eligibility and Pwd status but surely be able to change exam centre.

Hope this helps.