Hii Pavithra..

Yes don't worry, you can even change your signature during the correction period for neet 2019 application.

Correction period is from 14th january 2019 to 31st january 2019.

For neet correction guide check this- https://medicine.careers360.com/articles/neet-2019-application-form-correction-guide

Hope this helps you. All the best.