According to the notification issued by CEE kerala,  the online submission of NEET Mark's and addition of medical courses to your existing application can be done between 16th June to 21st June till 5 PM. If you have qualified Neet but haven't sent a application,  you can send a fresh application between 16th June to 19th June with your neet Mark's included. 

If you don't add up your marks in due time, your application won't be considered for selection.  

You can add your marks on the official website of CEE Kerala that is www.cee.kerala.gov.in. I hope it helped you.