Hello, If you have registered but were not allotted a seat in Round-1 & Round-2 you need not register again. But if you have registered in Round-1 & exited availing Free Exit or  registered in Round-2 & exited with Forfeiture of fees can register again with payment of fees. Fees will be based on category, For unreserved the non refundable fee is 1000 while for SC/ST/OBC/PWD it is 500. The refundable tuition fee will be 10,000 for UR and 5000 for the remaining categories. For the official fees notification refer this link https://mcc.nic.in/UGCounselling/Documents/UGSchemeFinal.pdf .You can check these links for more details on the mop us counselling process https://news.careers360.com/neet-2020-counselling-mop-up-round-registration-started-at-mccnicin

https://medicine.careers360.com/articles/neet-counselling .  The registration  will be closed on December 14.

Best wishes.