If you go through the frequently asked questions of national testing agency website then you will find the same question and their answers it that there should be no changes in the difficulty level of the exam it is just the organising body is changing from CBSE to National testing agency and there is no change in the difficulty level of the question paper.

hello madam 

donot worry about the tougher in the question paper 

actually the question paper will not compeltely high complicated 

according to me the neet will be compeltely allright no problem 

all the best