Hi aspirant

Hope you are doing well .It is clearly mentioned in the neet bulletin that the candidate can use his / her left or right thumb impression so you will not have a problem during your exam as your left hand was not well .

As  there is left time left in neet exam so you should be well prepared and be confident and below is the link for the sample papers .

https://medicine.careers360.com/articles/neet-sample-paper

Good luck

Hope it helps